Species Endangered (MS-Blog Series from) XIII / 09

Ganges Gharial

(Gavial)

Class: Reptile

Order: Crocodylia

Latin name: Gavialis gangeticus

Range: India, Nepal (Survives in scattered populations at some larger rivers; mainly the Ganges, Brahmaputra and Indus) – Earlier also at Bangladesh, Bhutan, Myanmar, Pakistan, but these populations now probably lost or nearly so.

IUCN: CR (Critically Endangered) / CITES: Appendix I

(about a 2008 situation)

Crocodiles from outer appearance are large aquatic (predatory) animals with strong bite and powerful armor. Because of that, the adult specimen have few potential threats at the nature, except that of man. In during the past decades(/centuries), the hunt for fx crocodile leather used in the various manufactures has taken it's toll on wild populations. More recently additional threats have emerged, as they also suffer from increased pollution of waters, ao.

In lack of any especial knowledge from that (ie hunt of crocodiles in the pasts, which probably was at most intensive before 20th century) it's noticed many of them been classed for the threatened already at 1970s. Actually, in that recent past, most/all of the species were found endangered, nowadays some are considerably better and only about a one third are more severely threatened. By very brief look one can also notice captive-breeding and farming of captured animals been sometimes found having had positive effect, although usually in the cases when crocodiles have been of some use/benefit for humans (in purposes of crocodile leather and meat production, etc). Because many of the species also mature rather young, the releases of the captive-bred animals have sometimes been of effective help in recovery of the wild populations.

As a group, the crocodiles are often said little changed during their long history, belonging for the most distant of surviving animals – kind of summarizing that, Halliday-Adler book mentions the Crocodylia having “Seen the Dinosaurs come and go” (in during about 150-65 Million year in the past). In overall (on the basis of fossil record), crocodylia at first raised as animal order about some 240 Myr ago. They are estimated have separated for their main lineages (commonly known Alligatoridae and Crocodylidae), around the Cretaceous (roughly before 65 Myr ago). After that, in later periods are the currently extant species evolved. The 3^rd from main lineages (the Gavialidae), separated of its own around Paleocene (around 50 Myr), perhaps even already during preceding Cretaceous. It is also considered more closely related for the crocodilians than alligatoridae. According to the traditional categorization Gharial (Gavialis gangeticus) is the sole extant species left in group, others having gone extinct well before the Pliocene (ca 5-2.5 Myr). (There's closer to 30 different Crocodylian species in the main order, if the some recently divided (sub-)species are counted as species on their own.)

Like the reptiles usually, crocodiles also give birth by laying clutches of eggs that hatch outside females body (so called oviparous form of reproduction). More especial for the crocodilians (and perhaps even surprising it being so) is their long period of parental care, which for some species lasts several months - Since less usually the reptiles fx guard their nests and more commonly juveniles just develop on their own once hatched. But in the crocodiles the parent (usually the mother) even helps the juvenile to hatch and carries recently born at its mouth. (As well, loosely related to previous perhaps, but according the book mentioned above the crocodile eggs are predated by various species ranging from ants to bears. But, like said, the adult specimen rarely have any natural enemies.)

More typical to reptile/not so unique for the crocodiles, is fx so called TSD (Temperature dependent sex determination). It's been shown that TSD imposes the sex ratio in many reptiles, but it is the sole governing factor for that in the Crocodylia, Tuatara and in some of the Turtles – The mammals, birds, frogs, etc generally instead have GSD (Genotypic sex determination). The latter probably is more recently evolved mechanism, supposedly. For the lizards and in some of the turtles (acc. to my understanding) both mechanisms are found in use; TSD appearing generally more common for the turtles, while (vice versa) GSD is more usual in the lizards.

In practice this means that from a complete clutch of eggs once laid by 'TSD-parent', the reptile juveniles born are usually of the same sex - However, the eggs laid on different levels (under the sand, fx) may develop in the varying temperatures and as result both male/female juvenile may develop. Generally, in case of the (many) turtles low incubation temperatures produce males and higher the females. At the crocodylia, this largely goes similarly like in the example from Nile Crocodiles, from which the book mentions study showing that incubation temperatures above 34.5 and below 31.7 (C) mostly resulted for female offspring, while in the intermediate temperatures male offspring was dominating. (For the crocodiles, TSD is likely universal – and no GSD is found to affect for their reproduction). (Halliday-Adler, p. 116-7; 215) To make things more complicated, however, various things have effect for the incubation, and not solely it is left for the surrounding temperatures to 'decide'; fx some turtles seem to select nesting locations favorable to particular sex ratios. As well, some of turtles - and perhaps other reptiles too - may even be able to manipulate their sex ratios (ie sex of their offspring) by altering level of hormones they allocate to their egg yolk, like also is mentioned. Even in case of crocodiles, hormones play some part in the process, especially at the transition temperatures that usually produce both male and female. All in all, the process (TSD) in the reptiles isn't yet completely understood; fx some lizards are known to have GSD, but certain temperatures in spite of that seem to favor producing merely females, the other males.(Halliday-Adler 2002, p. 116-7; 215) (And from the reason that any general source – as usual here - doesn't seem to show us any additional information, we can leave the subject for these brief simplified and very concise remarks.)

However, as the case of sex determination appears a rather significant question, also the concerns from current climatic effects have been raised aforth; especially how might the warming influence the sex ratios in some (TSD-)reptiles (various already vulnerable as result of other reasons)? Whatever most likely, usually they're also mentioned having survived past somewhat resembling periods and changes through the millions of years. So – simplifying the matter a lot, making guesses – one could suppose that reptiles which evolved in times of the warmer global climates by origin, maybe also have some other effective 'mechanisms' to protect their continuation and sex ratios from consequences of (climatic) changes. Not the least because they 'get by' with such curious manners as using external heat sources for to behaviorally adjust their bodily temperatures (like do the ectothermic / poikilothermic species); and contain also others that reproduce via ovoviparous birth and parthenogenesis, (fx). Or at least so we could assume...

More worrying, probably, appears the problem from the human created chemical pollutants. There's reasons say that sheer speed of current changes and various threats affecting the sex ratios (in reptiles) may hold possibilities of more severe changes than usually believed. Some reptiles are been shown/found noticeably highly susceptible for hormone-mimicking chemicals, such as the breakdown products of some commonly used herbicides, (fx). Also some pollutants, (the DDT-derivatives mentioned) are known to have feminizing effects on alligators as well as the turtles eggs. (For the positive side it's also mentioned that using certain hormones in captive breeding for produce females may be of some help in conservation efforts.) But, as well book mentions studies from the chemical alteration and environmental contaminants as causes of reduced egg hatching and neonatal mortality in reptiles (Although the example is from some time past, 1980s Florida, where the alligator populations of some lakes were found with abnormalities in their reproduction and endocrine systems, probably as result of pesticides exposure and nutrient pollution.) In overall, during the 20^th century man-made chemical compounds have reached numbers of tens or hundreds thousands. Not all appear harmful by effect, but some very potentially can influence the biology of animals altering their endocrine system. More typically noticed are the effects from certain chemicals which are used on agricultural purposes, but also there's some other mentioned of little concern until recently; the “inert” chemicals contain such as plasticizers, surfactants, and flame retardants, whose impacts on reptiles and amphibians not adequately known or haven't been studied so far – recent studies also are mentioned to have found (ao) the polybrominated biphenyls (Pbb) ubiquitous pollutants and as powerful hormone system modulators. (Halliday-Adler 2002, p. 215; 222-223) No wonder there's arguments presented against the use of above mentioned every once in a while...And since we're basically altering ourselves to same compounds we're spreading for the nature, one could say that (some chemicals) probably have part on the male sex hormone declines and the reduced overall fertility, often more commonly noticed topics at the usual discussions.

But seriously, its by all means reasonable to notice that the possible impacts from many of these aren't probably at all sufficiently known. Also since some pollutants are been in use only for some decades until present, their long-term effects and consequences are still unknown. Even that a certain particularly harmful have been prohibited for some time, like the DDT. (In spite of that, it is also mentioned still used as a pest killer in some countries, usually in the tropical regions.)

Less especially a matter concerning the reptiles but many other animals as well, are problems from 'regular pollution' that contaminates many the larger river systems and small seas. Unfortunately, many species living in them are endangered/affected by various other factors - in addition to some most typical are the past and current hunt of animals, and the damming of the rivers (can have harm the animal reproduction success, survival, etc., although other aspects concerning the human water use are perhaps more often noticed.)

Anyway, the stress on river systems for uses of energies production is more likely to increase, than the reverse. According to World Development Report 2010, from planets freshwater only tiny small percentages are in the rivers and lakes, and further from that only about 10 per cent used in the renewable energies production (agricultural uses make the largest part, closer to 70 per cent – although these types of use aren't strictly comparable). But, about half of the total renewable electricity of the South Americas, fx, is mentioned produced with hydro, and in some other parts of the world where there's still 'unbuilt' water power (rivers) the use is expected to still increase. (Above information from various parts of the report; Overview, p 6.; Chapt. 1 and 3) Likely, the hydro remains a source for large part of renewable produced electricity in future. However, there's also various co-effects from the water power if it's built on riverine systems.

In addition to fx crocodiles, there's plenty unique large species that live in the rivers at various continent (or in the river deltas). The threatened (from various reasons, of course) contain fx most of the river dolphin species, like Yangtze river dolphin (CR - mentioned possibly extinct), Ganges river dolphin (Platanista gangetica, EN), Indus river dolphin (P. minor, EN), Amazon river dolphin (Inia geoffr., VU) and La Plata Dolphin (VU – appears on Amazon delta and/or some S.A. coastal shores). From the Crocodylia similarly threatened are at least the Philippines crocodile (Crocodylus mindorensis, CR, - probably rarest from crocodiles), Siamese crocodile (C. siamensis, CR, - equally rare) Orinoco crocodile (C. intermedius, CR), Mugger (marsh crocodile)(C. Palustris, VU), Cuban Crocodile (C. rhombifer, EN), Chinese crocodile (C. Sinensis, CR) - Listing based on information from Beer-Morris book, mostly, and not generally checked other sources for their more recent situation. Also there's various other; like many (larger) fishes (ao), from which the common knowledge also tells that in the past the fishes used to be not only more plenty, but also larger from size. (Again, possibly as much variety as river systems appears, some being at recovery from past effects, and some perhaps only recently have come under increases of waste and other consequences of human large-scale uses of land and waters.)

Gharial is an ancient species, and the young specimen at least appear very vulnerable to pollution (a serious concern hampering the recovery, like noticed in this news-briefing.) It is also been protected from since 1970s fx to prevent the poaching losses and there's been captive-breeding programs to aid its recovery for some time. India being a country with large population and a lot of poverty, it's mentioned that gharials earlier breeding areas have in time become occupied by human settlements. Decline at the latter part of the 20^th century was rather steep since still in the 1940s there probably was about 5000 – 10000 animals left in the wild - the page also lists some other reasons for decline like the humans collecting the crocodile egg, reduction of available diet (the fishes decline), and as well specimen harvested and killed for human uses, ao in the (traditional?) medicinery. (Also mentions from the establishment of Gharial Conservation Alliance, GCA). Additionally, fishers often regard gharials as direct competitors and destroyers of their nets. From other things, it's noticed that Gavials only lay their eggs on sandy shores of river (those are only places where they come ashore), but such peaceful breeding sites have become rarer too. Eggs are also often washed from the nesting areas by floodings, etc.

Crocodiles in general also suffer largely from being feared as threat to humans. Indeed they are effective predators that can attack any kind of suitable prey coming for river sands/water edges (But, just two species – the largest - are mentioned as reputable man-eaters; the Nile Crocodile (C. niloticus) and the Salt-water Crocodile, Estuarine.) But not the Gharial. Although they can grow about as large as the above mentioned species, they are almost exclusively fish-eating from diet. Larger individuals supposedly sometimes also eat smaller birds and reptilia. Although, they may scavenge anything found on the rivers, also perhaps remains from the corpses placed on river in funerals; But as result they're also believed as man-eaters.

So, more generally, in addition to hunt, pollution and changes of their natural eco-systems (among other things), there seems been various things causing it becoming conservation dependent and nowadays classed among the more severely endangered. The decline can be timed in the modern times, since traditionally they are mentioned been considered as sacred animals. However, since we find it rather recently classed as CR – downlisted from earlier status - but have no further information to present, it's better to check some other sources for additional information too, (fx) the links in the text. Not the least because our sources – as usual here at MSW – appear to present rather differing figures from the total amount of individual animals left in wild populations (;fx Beer-Morris book lists fewer than 2500, but often only 200 is mentioned.) So in this case, one who's interested can probably also check the species status from IUCN Red list (on Gavialis gangeticus) – as it also presents the information from amount of the adult breeding specimen, fx (and has also other more precise information from their current conservation status).

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Sources:

Beer-Morris, 2005, Encyclopedia of the endangered animals. Grange books.

Halliday, T. – Adler, K., [2002], The New Encyclopedia of Reptiles and Amphibians. N.Y.

[W.B's] World Development Report 2010: Development and Climate Change (2009); at http://go.worldbank.org/ZXULQ9SCC0 [ Pre publicat. version?? ; read pre 15th Oct.]

[Pics from Halliday-Adler : Above; Three Gavials on river bench , Below; Alligator juveniles, Florida]

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Species Endangered (MS-Blog Series from) XII / 09

Gastric-brooding Frog

Class: Amphibia

Order: Anura

Latin name: Rheobatrachus silus / R. Vitellinus

Range: (Australia) - Inhabited a limited ranges at eastern Queensland.

IUCN: EX (CR) / EX (CR)¹, CITES: -/- (not checked)

(a 2009 situation)

Sometimes word of the day, frogs are more important than people usually realize. Them are – like echoed also by us in our earlier amphibian post – supposed most threatened from the animal orders, not the least by the climatic change, etc. But, as they also are often mentioned having been first species that moved from seas to the land, one easily presumes them most 'primitive' of the terrestrial animals. In fact that appears false assumption, for we learn that their extant main groups (Frogs, Salamanders, and limbless Caecilians) actually are timed roughly for the same periods as the modern reptiles. Oldest from reptiles still extant genera, turtles and crocodiles therefore appear slightly more distant from evolutionary origins than current amphibians families, it seems. (However, also appears stated that earliest amphibians were around some 300+ Million years in the past, already). In spite of how exciting these preceding view-points might be, our interest in this (brief) text is delimited for the variety of colourful amphibian species. Since the rain forest species are not only most numerous but most impressive from looks (as well most threatened of them, also often said), this consists largely from representing them.

So, the above frog(s) examples for this part, are not selecte from the reason of being extinct – actually they represent only singular species among several mentioned in this text. Nevertheless, and like we find mentioned, the Rheobatrachus (genus of frogs) contained above mentioned two species (R. Silus/.Vitellinus), both rather exceptional. Mentioned as gastric-brooding frogs from the reason that in both the reproduction was by female frog ingesting it's (fertilized) eggs, which then developed for juveniles in the frogs stomach (and were finally vomited as juveniles from it's mouth). Unique manner even among the frogs which show multitudes of variety and peculiar examples at their reproduction. In our only marginal acquaintance from the life of the frogs, this makes us almost to think the truth often being stranger than fiction.

Anyway, sad part of course is that no Gastric-brooding frog seems been found after their rapid disappearance during brief period in begins of 1980s (Been only known for science since about 1972/3). At that time the reasons and causes for frog extinctions in general weren't yet too clearly understood, and so, in lack of any especial knowledge from the species we're not focusing on that here more precisely. However, at the amphibian declines generally, an increased vulnerability of the small frog populations is nowadays often mentioned. Most alarming prospect, equally often noticed, is their habitat fragmentation(/destruction), like mentioned in following paragraphs:

"Shrinking Habitats. Pressure generated by the world's expanding human population creates an insatiable demand for land that results in the destruction of the natural habitat of plants and animals. This process is offset, to a very small degree, by the creation of natural reserves, but these can become prisons rather than havens for animals such as amphibians. Many amphibians live in small, local populations, the longterm survival of which depends on the occasional immigration of animals from other such populations elsewhere. Increasingly, amphibians are being forced to live in fragmented landscapes within roads, built-up land, and agriculture separating one population from another. There is growing evidence that this isolation leads to an inbreeding and a consequent loss of genetic diversity, decreased survival rates and an increased incidence of anatomical deformities.”(Halliday-Adler 2002, p. 32-33)

As well is said: “Although amphibian population declines have attracted a great deal of scientific and media interest, there is no reason to think they are unusual or unique. All the factors that adversely impact upon amphibians pose a threat to other forms of wildlife. [...]"(Halliday-Adler 2002, ibid.) ...Remarks at the book then continue with mentioning the disappearance in freshwater habitats noticeably having impaired the amphibians populations for some time (other wildlife as well). Also, fx how the protected areas should be designed to create optimal conditions in nature reserves is stated being increasingly important, since the populations based on single limited area are more likely to face eventual extinction, sometimes despite protection. As well appears noticed, that for smaller part/some level the diminished habitat can be replaced by habitat creation - like the underpasses and tunnels built in some places to create amphibians some safety from roadkills, fx on routes for their breeding sites (ao efforts at their protection mentioned). (Halliday-Adler, p. 33-35) Remembering that (in cases) populations of thousands individual frogs have been noticed rapidly vanished (as result of increased vulnerability to variety of threat), also gives some importance for the above mentioned.

The amphibian decline in overall presented at our earlier post, we'll leave that for these few words and the following text mostly serves the purpose of presenting examples from variety in the amphibian lifes. But, fx the Amphibia web's pages about the global decline contain some further information, probably (also seems contain the downloadable Amphibian Action Conservation Plan). And for the interested, from various threatened amphibian around world, EDGE's Amphibian top 100 list presents many, any of those less usually or not commonly noticed. (And – further more - not forgetting to mention this word on behalf the amphibians ; we also learns from it about another exciting frog species, the Phantasmal poison frog (EN), whose skin secretions contain some particular compounds, possibly found of use in the human medicinery as well as aid in the research of pain-killer medicines (or something like that, sounds not at all too unsual or surprising, concerning the amphibians have especial skin formations in overall, etc) - Even though I find that least interesting from aspects presented on the text (Maybe so 'cause I don't much care from the medicines markets and labs, and even less from the prospective views of the global medical businesses or firms. Nevertheless, despite my slight antipation, it's sometimes mentioned that penicillin probably has been one of the most benefiting inventions in the preceding century - for human kind.)

...But for to stay on our main topic in this; following paragraphs are focused on colourful and exciting characteristics of the amphibians. Many of the species mentioned in the following, I suppose, are from the better known colourful and sometimes also the most usually represented examples. In spite of that, there's a lot especial and interesting in them to familialirize with (So I noticed when writing this...).

Often in the nature, bright colour serves purposes of aposematism (ie as warning sign to potential predators from species being distasteful/of it's toxic defenses). Some frogs also exhibit polymorphic appearance (different colour patterns found even in the individuals of same species). From this, again the most popular examples are to be found in the small toxic frogs of South American forests (Presented in the pic above), that appear in variety of species (there's at least three separate genera of these tiny frogs with toxic defenses). Variability in the skin colour and pattern also more generally appears typical to amphibians, as well as does the sexual dimorphism; In several cases male and female frogs exhibit rather different looks, fx. Further more, some are mentioned changing their overall skin color according to body temperatures – not quite same manner or as impressively as the chameleons, but some fx change their tones of color according the surrounding environment or frogs mood (like mentioned from the European leaf frog, Hyla arborea (LC) - also, when exposed to sunlight it appears paler by color.)

Colour patterns appear as method to warn their would-be-predators, but it's also found commonly used as camouflage by the frogs - to avoid detection from potential prey. Most frogs are carnivores - about majority eat insects but larger species also various other prey and fx typically the diet of some rain forest frogs ranges from worms and little snakes to even small mammalians (like bats, fx). To hide from their prey, certain species are found having adopted/imitating the usual background colors, even to level their skins reflecting smaller variations of litter and leaves found on the forest ground. Some horned frog species most typically mentioned examples from such adaptations. (Another interesting example, ao, we find presented in the pocket guide from East African frogs [2006]; in form of (Tanzanian) reed frog species (Hyperolius Orkarri), whose overside colours are mentioned closely matching the granite rock environment it lives at – Acc. book species is only known from few areas).

From the use of colour as warning from species palatability, there's also plenty examples at the Salamander (Caudata) families (Perhaps, not so evident of the species in pic above, Golden-striped Salamander, Chioglossa Lusitania, VU) - Salamanders and Newts form a parallel group for Frogs and Toads, the Newts being (in general) more accustomed to watery environments and Salamanders usually more terrestrial, except during their breeding periods. They typically are impressive from appearance and colour; An european species most renown of them, Fire Salamander (Salamandra salamandra, LC) represents very bright yellow colours. It has also interestingly given reasons for many odd beliefs in the past. According to the most usual from these, it was in the Middle Ages widely asserted capable of setting up fires by its sole presence and also (was believed) resistant to flames. According to another often mentioned anecdote, this false belief was already widespread and common during the Antique; Even to the level that Pliny the elder (23-79 A.D.) experimented it's accuracy when preparing his renown book, Naturalis Historia; - by throwing the fire salamander into flames, with expectable result of course. As noticed, that apparently didn't prevent the same false belief to persist through centuries for hundreds years afterwards.(...the underline on this added 28.08.2015) (Serves well also to show how a mistaken belief and fallacy can remain, and in time become part of the shared common consciousnes.)

But, from the real qualities of the Fire Salamander, it's fx mentioned that a lot variation appears between coloration of the individual animals. Some are almost completely yellowish, some represent only small bright dots. Many other salamanders as well represent by bright color a warning from their toxic defences (even though that doesn't completely prevent them being predated) – however, I've not checked if that the case also in genus plethodontidae, salamanders that are mostly renown from breathing only through their skin since they do lack the lungs completely. As for other interesting salamander characteristics, it is mentioned that some species - like the N. American Eastern newt (LC)(Pic below from Eastern Newt in the eft phase, adults are mentioned differing from color) - can find their routes from several kilometers distance for the watery streams and ponds they've been taken far away from. Even more, it's mentioned that they are able to use the position of the sun, with the aid of sensing polarized light to perceiving their position and using that (information) for directioning. As well mentioned, it been demostrated that they are able to detect Earths magnetic field and use that to form some kind of 'maps' from the surrounding environments - having sort of "GPS-system" of their own; ie it is noticed suggesting that the Newts nervous system maybe able to develop and store some detailed information from their living regions. (Halliday-Adler book, on p. 52). (How precisely/how well that mechanism is understood/studied, I've not checked, but there's a few researches from the subject listed at the end of this post). Actually, various animals similarly use some kind of 'compass' to make their routes and journeys, most renown are the migrating birds. Salamanders, whose plentiful families are distributed around the most continents (excluding the Africa and Australia), appear likewise threatened as the other amphibians by varying degree – 3 species are listed critically endangered, at least (Halliday Adler, p. 56-59).

Next we briefly devote also few words for other amphibian typical features, mainly on the diversity in their reproducing. First, there's this exceptional case in point in form of the South-American mouth-brooding frogs. In their case (the male) frog carries small tadpoles/froglets in it's vocal pouch, also providing nutrition them, and from where the fully developed little frogs then emerge.(Halliday-Adler, p 27-28). Mouth-brooding frogs include at least the species we find presented with the name Rhinoderma darwinii (VU) - listed so from it's observed decline in part of range, though mentioned still rather common on some places (acc. its IUCN Red list data sheet on Rhinoderma darwinii). Most frogs, however, do reproduce by their more common manner, laying amounts of eggs on water sources (which usually are fertilized externally). Especially the rain forest species, however, have developed additional strategies to their breeding and protection of the juvenile.

A manner used by many from tree frogs is to deposit eggs on vegetation/leafs overhanging the water, (also typical to the reed frogs, a group in the African arboreal frogs with over 120 species)(Spawls-Howell-Drewes 2006, p 184). The eggs later drop for the water where the tadpoles then start their metamorphose (for a frog). There's also species whose eggs are developed in certain 'foam-nests'. When the edges of the nest dry it falls for waters below. The inner in the foam nest remains moist some days, allowing the tadpoles to emerge in it. In some cases the creation of the foam nests involves lot group-behavior by frogs, the foam released by female frog(s) and forming the nest between leaves, which is then 'hardened' from it's outer surface by several male frogs hangin' on beside nest's edges.

Further more, there's as well many that use some alternative method like depositing them eggs in the burrows dug near the edges of the seasonal (water) pools - after the rainwater floods for pools and finally enters burrows, tadpoles swim for the open water.

(Like in the exemplary case from (East-)African Guinea Snout-burrower, interesting looking species from genus we find provided with the name hemisotidae, mentioned at Spawls-Howell-Drewes (2006) book). (Species pic above)

Somewhat more especial, may appear the reproduction of some of the earlier mentioned tiny (S. American) Poison dart frogs (from genus Dendrobates), species that live mostly within the leaf litter on level of the rain forest floor. Fx, in the case of some of the Strawberry poison frogs (D. Pumilio, LC), the frog first lays its eggs on leaves and carries the hatched tadpoles (under the protective foil on frogs back) to the axils of certain plants, or, to cloaks of trees in some cases. These contain small level of water in which the tadpoles grow to small froglets (number of other species also live in these aquatic micro-environments). The female frog also feeds tadpoles with the unfertilized eggs. Some Madagascar frogs are mentioned with somewhat resembling manner at their reproduction and 'parental care'.(Halliday-Adler 2002, p 28-29) Yet, further another exceptional method (in the variety of frog breeding) is maintained by some another South-American species that we find presented as 'Marsupial frogs', or Rana marsupial (Gastrotheca ovifera, EN). In that case eggs are first directly fertilized and each is placed to a certain protective 'pouch' on females back, where they remain in moist and pretty safe until emerging as fully developed froglets from there - and the juveniles when 'born' seem to bop directly from the frogs back. The species also is mentioned endangered acc. it's IUCN listing (IUCN Red List data sheet; Gastrotheca ovifera). Various other frog species carry their fertilized eggs on the adults back (/or, fx attached beside frogs legs like the Midwife-toads). Most usually the developed tadpoles are just dropped for water to develop. (I guess this variety of frog breeding methods only presented by brief look for the topic in above sentences... but, seems quite adequately covered, so let's leave it for that now.)

Finally, this kind of gallery of frog wonders and especial features cannot do without mentioning the 'flying frogs'; A species group comprising from the Asian (arboreal) forest frogs, that glide long distances (from tree to another) with particularly developed formations in limbs (webbings, spread for like parachutes/gliding surface, that 'permit the kermit' for “fly”, very seemingly) Among these we find a species provided with name Rhacophorus nigropalmatus (LC); or Wallace's flying frog after A.R. Wallace, 19^th century naturalist explorer also presented in our recent post. (The Indo-Malaysia islands Wallace journeyed contain various animals first recognized by Wallace and therefore named after him ; from the birds most renown are probably the Moluccan Megapode (Eulipoa wallacei, VU) and a paradise birds species Wallace's Standard Wing (Semioptera Wallacei). He also describes both quite thoroughly in the book.) For the flying frog(s) Wallace also devotes a few paragraphs, though far less in lenght than descriptions from the above mentioned species - But, it wouldn't feel too surprising if some frog species would also be named after him. In overall the Rhacophorus frogs belong for the Afro-Asian tree frogs, and in addition to this example mentioned genus/group contains number of other glider frogs. Recognized as separate species only later, perhaps. (Pic below; Wallace's flying frog)

But, for now we'll have to cut this in brief, since this only was meant to present some ordinary examples from that variety and overwhelming richness of life - From the amphibians in their about 6300 recognized species in existence worldwide and some even mix together and/or are not clearly differentiated from near similar/co-species. Many of them vulnerable to various threats, Climatic Changes the most often mentioned of those. Anyone can also easily search further details from the mentioned few species we were able to present in this (and from various other; fx, nothing we were having time or space to present from the vocal communications of the frogs, or about some other things - like from the species especially adapted for watery environments/lifes; the leaps and bounds of the frogs; not much anything from most of the popular families – like the arboreal tree frogs of the Central-/South Americas noticeable from them slender and curious looks, and most often presented in the natural books pics...And whatever else has recently been researched from amphibians and their evolutionary histories, obviously.)

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Note:

1. Species also presented with the CR listing, since both seems been moved to the category/status of EX rather recently. (In the IUCN fact sheets listed as extinct about the turn of the century. But, what a happy surprise it would make if some surviving specimen/individuals still would turn out to be found, somewhere, even that it seems very unlike possibility.)

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Sources/other information:

La Marca - Manzanilla 2004. Gastrotheca ovifera. In: IUCN 2009. IUCN Red List of Threatened Species. [Version 2009.2.] <www.iucnredlist.org>. Downloaded on 19 November 2009.

Ed Meyer (et al) 2004. Rheobatrachus silus. In: IUCN 2009. IUCN Red List of Threatened Species.[Version 2009.2.] <www.iucnredlist.org>. Downloaded on 19 November 2009.

Jean-Marc Hero (et al) 2004. Rheobatrachus vitellinus. In: IUCN 2009. IUCN Red List of Threatened Species. [Version 2009.2.] <www.iucnredlist.org>. Downloaded on 19 November 2009.

Carmen Ubeda (et al) Rhinoderma darwinii. In: IUCN 2009. IUCN Red List of Threatened Species. [Version 2009.2.] <www.iucnredlist.org>. Downloaded on 21 November 2009.

Halliday, T. -Adler, K., (2002), The New encyclopedia of Reptiles and Amphibians. N.Y.

Spawls-Howell-Drewes, (2006), Pocket guide to the Reptiles and Amphibians of East Africa. London.

Magnetoreception at (some) amphibians;

(Both studies from The Journal of Experimental Biology)

Brassart, J [et al], 1999, Ferromagnetic material in the eastern red-spotted newt Notophthalmus viridescens., (JEB) Vol 202, Issue 22 3155-3160

Phillips, John B. [et al], [2002] `Fixed-axis' magnetic orientation by an amphibian: non-shoreward-directed compass orientation, misdirected homing or positioning a magnetite-based map detector in a consistent alignment relative to the magnetic field? , (JEB) 205, 3903-3914

[ Pics at the text from Halliday-Adler book; except the Guinea-Snout burrower from Spawls-Howell-Drewes.]

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Intermission (III.) / Anniversary 100th post

Celebrating mildly this important land-mark (the 100th post) on the paths of the MuleSkinner Blog, the cake is prepared and served (however, since we have no time for celebrations, this post is instead cooked of folk-tales and wonders of the nature...)

...Our butterfly-series now completed, we nevertheless devote a few lines for them here. Species is considered to be one of the most cold resistant in the world (or indeed it's larvae which overwinter). It's the Scarce Copper (L.Virgaeuris). In butterfly's populations of the most northern area (which reaches beyond the Arctic circle - probably quite northern range for a butterfly), the larvae has capability to produce glycerine/or, glucose (apparently, the same compound as used in the cars as fuel antifreezer). A single larvae produces amounts of over one third from it's own weight permitting then the survival through most extreme winter colds. In the spring when the warms arrive the liquid disappears from it's body systems and later metamorphosis takes place. (It also is common at some mountain ranges on other areas, whether these also have developed same method for overwintering wasn't mentioned...seems less probable, somehow)
...and perhaps it's not even sole example of that kind, but anyway pretty exceptional and not the less surprising than anything we find from these natural wonders...

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The (folk-) story part is actually good old tales from the Brer Rabbitt. (Whether the story's really folk-tales or has been invented by some artist at Walt's firm I have no idea, 'cause I only have it at the old W.D. children book series. But it's named as Brer Rabbit and his Friends in the original book.)

In this ordinary story, the Brer rabbitt fools with the Fox and the Bear as he usually does (Fox and Bear, as usually, try to catch him for the dinner). However, they have the idea for to make a rabbit replica from glue and when the (Brer) rabbitt then meets his 'double', he gets angry because that is not answering his compliments. Soon after, from hitting the doll, all his limbs and finally the whole rabbitt is stuck with the glue. Fox and the bear think they've finally catched Brer Rabbitt...but as usual it all ends well for the rabbitt, since being clever he soon tricks them to throw him for the brier (bushes), where he lives.


(Having not familiarized myself with rabbit lifes and ecology, I've always wondered if it's just in the fairy-tale that the rabbit is homing in the briers? Or do some of those actually inhabit the bushes? Of course, that's rather secondary of importance; in the story seems like he does. (picture below) (W.G.)

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Species Endangered (MS-Blog Series from) XI / 09

White-backed Woodpecker

Class: Avia

Order: Piciformes

Latin name: Dendrocopos leucotos (leucotos)

Range: Wide but scattered range; appears on suitable forests across the Euraasian continent and Asia (and as far east as Kamchatka And Sakhalin).

IUCN: Not listed(probably), but species locally endangered in some countries /CITES: -

(approximately a 2000s situation)

The birds have been remarkably few of appearance in preceding posts at these series. That absence may have been from the wide variety of available genera, but likely is also resulted from the difficulty to select representative example(s). However, this part generally focuses on woodpeckers and for the lesser extent other (endangered) birds. Also makes an example from locally endangered species (Acc. to information we find, the White Backed-Woodpecker – with the several subspecies - has in overall large range and it's therefore not counted among the particularly threatened, birds global population estimated closer one million individuals)(Birdlife Internat., 2009 species fact sheet) Locally endangered animals in various countries of course are not limited to birds, but there's examples from as various as crocodilians, insects, and others. -> Bird pic beside; Dendrocopos leucotos.

Like noticed (in the earlier posts) the land birds, particularly those endemic to islands and habiting the restricted ranges, contain many that historically have been affected from human purposes. In spite of that, (important to notice as well) the birds also represent most widespread from the animal classes in the world; excluding humans they solely inhabit all eco-regions (ie continents), including the Antarctic and various Oceanic islands.¹ And that being so originally, even without human accidentally caused/intentionally brought species introductions. The especial features for birds aren't limited just in their capability for flight, but there's other evolutionary 'novelties' like their feathers that make birds (often) better resistant to cold and wet than most other animals. According to current knowledge (I suppose) feathers are believed having evolved for birds preceding the capability to fly. That, and the birds having stable body temperatures (like mammals) make some important factors having permitted their spreading almost everywhere in the world.

From the origins of the birds there's nowadays probably a lot varying research/studies, if not too stone cold complete detailed theories. However, since this part only focuses for woodpeckers, we just refer for their origin and pasts (perhaps in some later post more from bird evolution can be presented). Woodpeckers (The main group, Picidae, consists of wrynecks, piculets, and 'the real' woodpeckers) are believed by earliest origin to date as far as the early Eocene period, roughly 50 Million years ago(Mya), although the mentioned still extant sub-families appear believed younger; In the fossil record, the earliest forms from these being found from about the mid-Miocene, ca 15-10 Mya.

Generally woodpeckers are birds adapted for various different forest environments – which also makes an argument on behalf their selection here. There's about 200 species in the Picidae. In addition to largest part adapted for life in forests, some variation and exceptions appear; fx, there's species inhabiting the deserts (and making their nests on cactus, fx) or even some adapted for more unusual habitat for woodpeckers (fx those having abandoned trees and making nests on the ground, at burrows). Usually, again with plenty of exceptions and specialization, many woodpeckers eat small insects they seek from the suitable trees (typically fx aspen, birch in places where these appear most common from broad-leafed trees). Woodpeckers also hollow their own nests in the trees. When abandoned, those nests are also often used by other bird species. But, like many animals, also the woodpeckers are most numerous from the species that appear in the tropical forests.

Like is commonly known, most real woodpeckers are noticeable from their impressive behavior of 'drumming' (or pecking), a practice that also serves to signal other individuals their territory range (or some other purposes...) That is indeed very impressive sight, seeing a bird hammering with repeating rapid series of pecks high at the tree top. Because of that they are also sometimes easier locate in forest, even though they tend to avoid human watchers eyes flying less usually over open spaces or rarely at the level of the lowest twigs - However, again there's exceptions to the general rule and various species typically feed on insects, often ants, they seek on the forest floor level. Woodpeckers brain-cases, particularly strong necks and bills are especially evolved for pecking, that permitting them also excavating their nests. As another adaptation the woodpeckers feet is somewhat specially structured for to keep it firmly stable when pecking , fx.

From other typical features, also in our exemplary case, is them being often birds that keep rather permanent territories, only some specimen occasionally wandering for more distant areas – Which perhaps makes them somewhat vulnerable for human caused habitat destruction when compared with birds known more adaptive to various environments that sometimes may effectively enlargen their ranges; (Fx, from quite opposite behavioral practices we find an example of the common Starling (Sturnus vulgaris) which has been human brought to various continents. In the case of it being introduced for the New York Central park at 1890s with population of about 100 birds, it was in just about 50 years found having spread on the ranges from Mexico to Canada. Although, a bird that commonly habitats urban environments it's not found spreading as fast in some other region.) (Perrins, 1990) But there's also birds that happen take benefit from human activities more directly; like some seagulls that eat also human left-overs - and appear commonly on harbours, wastelands, where there's plenty of food for them. Returning to woodpeckers characteristics, we find them typically local birds, often overwintering in their living region (yet there are species which migrate even for great distances). As from outer appearance (many) from the actual woodpecker species are noticeable from black/white main colors, with the red or yellow area on the crown of the head. Sexual dimorphism is also typical, males having somewhat stronger coloration and usually being slightly larger by size.

Even though these birds (Picidae) show variety of genera, many adaptive to different environments and probably most species not threatened, there's of course some that are: fx from the largest the Ivory-Billed Woodpecker (Gampephilus picus, CR) are mentioned among most endangered birds in the world (Imperial Woodpecker, as well, that for some time seems been considered probably extinct). From the reasons to the decline/scarcity of the former mentioned - in during 20^th century - we find (not surprisingly) the reduction in the suitable habitat areas it favored. For comparison, it's noticed fx that some other from the larger species, like the Black Woodpecker (Dryocopos martius) and its american 'cousin'/resembling species(both about the size of the crow), are still rather common. However, both appear at various kinds of forest, although they also need to maintain large territories to find adequate amounts of food. From the other large species - actually mentioned largest from the still common species - there's one East-Asian species (which the source presents with name Great Slaty Woodpecker (Picus mullerensis, LC). Although, it's also mentioned mostly inhabitant of the natural forests. Various other species that appear on more limited ranges may be more or less threatened, but for this we've not checked other examples.

(Not necessarily especially related to any of the preceding examples– but according to some studies the existence of deadwood in their habitat area was found favouring some woodpecker species/increasing their populations.)

From the woodpecker selected as particular example in this post, like said before, it's not considered globally endangered (and not listed in the IUCN Red List, therefore). However, similarly like it there's various animals under the threat of disappearance in some countries, even that they may be more common in the other. This typically also causes some difficulties for their protection. Fx, some migratory birds may be threatened in their usual region, while they're not always considered so in the countries along their moving route/overwintering area. Because of that, there's intergovernmental treaties, like the UN-backed Convention on Conservation of Migratory Species of Wild Animals (CMS), also known as the Bonn convention, aimed for protecting the migratory terrestrial, marine and avian species throughout their ranges. Also, there's wild animals, whose population in some place may be migratory while the population(s) on the other region/country appear not - like in the case of Japanese Crane (Grus Japonese, EN), which has populations on Asian main continent and Japan.

White-Backed Woodpeckers (that are not migratory) appear rather common also, although they are mentioned on slight overall decline. In the Europe, they can be found usually in places where there's (often the conserved) larger woodlands and/or lower mountains elevations with sufficient forest cover. The bird probably has quite steady populations on some east Europe countries like Czech, Slovakia, Poland, Bulgaria, comparable in numbers (sometimes) for those of fx the Black woodpecker – Although, neither on this basis seems to occur close as abundant as the Great Spotted woodpecker (Dendrocopos major) in some areas <- bird pic left (It closely resembles Dendrocopos l. , though the Dendrocopos m. is slightly smaller in size, fx - and actually I'm not quite sure if I could easily tell one from the other even at close distance). In some other countries of the South-/East- and Mid-European ranges White-Backed Woodpeckers usually appear with somewhat more varying populations. (acc. Birdlife Internat., 2009 species fact sheet). - Since the map doesn't present us current estimates from it's northern range (Scandinavian countries), we'll only basing following on other sources from about 1990/2000s situation; It perhaps wasn't originally there such frequent in the first place, because this makes the far northern edges on the global population. Yet it was relatively common until recent times. Since about 1950s it was been in apparent decline (in Finland from about some 500 breeding pairs to quite recent estimated 50-70, and in Sweden maybe even more declined, the remaining populations limited to few areas. In the Norway, mostly appears closer the Atlantic coastal side where its more common – possibly because the climates and ecological regions there appear slightly different and more favorable to it, I would suppose)

Main reason (/most affecting single factor) for the noticed decline has been the disappearance of larger deciduous forest areas in mentioned regions. As result it's also believed probably having lost parts of its former territorial range for the Great spotted woodpecker, which more easily inhabits also the coniferous forests. In comparison the Dendrocopos l. is more demanding from it's diet and mostly feeds on certain insects that it digs from broad-leafed trees like aspen. Therefore it needs particularly large ranges of the broad-leafed forests and these were continuously found reduced in during 20^th century, largely because of the forestry economics favoring more timber productive coniferous trees.

So, this presented mainly as an example from locally endangered bird, but also from how any human forest use can change the conditions for the species adapted to particular habitats, fx. In principle the forestry management affecting it's decline (mainly) was maintaining - in some ways, acc. to levels of the time at least - rather sustainable practices; fx about same amount of the trees that was felled was (about) yearly planted, number of timber taken controlled in overall. (There's always other changes from the forestry use, fx the machinery 'mutilating' the ground, even though the long-term effects from that are often considered/argumented only limited. - Anyway, as an example from the locally endangered species this perhaps doesn't present a case too much generalized, but from human use and caused changes in the environments this is probably more typical and not at all unusual example.)

...Further from this, view the MSW book recommendations #28 (W-G.)

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Note:

1. Although, this point-of-view doesn't take into account marine species, since they are usually presented separately from quite logical reason. In Antartica there's plentysome regular marine mammals as well as the fish and some other habitants of the seas. Penguins of course are most well-known of the birds (them being terrestrial birds) but there's birds nesting in some coastal areas fx. And perhaps various (pelagic) species.The human inhabitants are limited to people at research stations (even if these are permanently populated nowadays, even).

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Sources:

BirdLife International (2009) Species factsheet: Dendrocopos leucotos.

Downloaded from http://www.birdlife.org on 13/10/2009

Perrins, Christopher M. (Ed.), (1990):The Illustrated Encyclopedia of Birds.

(Wikipedia ; Picidae/White-Backed Woodpecker)

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