Archives for November 2013

Croaking science is a new way for student volunteers and scientist to explore what’s occurring in the world of Science – science facts, new research or old debates which are inspired by or affect amphibians and reptiles, and then communicate this to a wider audience in their own words. The aim of the feature is to provide a platform for those starting their foray into the world of science communications as well as established scientists.  We welcome any submissions from students and scientists. Please note that the views expressed in the articles are not those of the Froglife Trust.

This is the time of year where you may be getting together with friends and family for meals all over the world. When you do, think about what this frog went without, to look after it’s young. From one of our new Croaking Science Volunteers Hannah Graves.

Gastric-brooding frogs were discovered in Australia in the 1970’s ⁽¹⁾. There are two known species, the Northern (Rheobatrachus vitellinus) and the Southern (R.silus) ⁽²⁾, neither of which has been seen in the wild since the 1980’s ⁽³⁾. It isn’t known exactly what caused the demise of the two species, it is believed that logging and disturbances to the water quality in their habitats may have had an effect on the Southern species ⁽⁴⁾ and wide spread forest fires and habitat destruction could be implicated in the loss of the Northern species ⁽⁵⁾. As with all amphibian populations globally, the fungal disease Chytridiomycosis can’t be ruled out ⁽¹⁾.

As the common names suggest, this genus of frog had a very unusual way of caring for their young. After the female had mated, she swallowed her eggs! This meant that the tadpoles could develop in her stomach safe from predators ⁽⁶⁾. After six to seven weeks the tadpoles metamorphosed into young frogs and crawled back out of the female’s mouth ⁽⁴⁾. During this brooding period the female switched off the production of hydrochloric acid to prevent digesting her young ⁽⁷⁾. This meant that she couldn’t eat whilst carrying her young. Just four days after her young emerged, the female’s digestive system returned to normal and she resumed eating ⁽⁴⁾. Unfortunately, as the two species are now classified as extinct ^{(1) (8)}, it is unlikely we will ever learn the secrets of how they managed to shut down their digestive systems and then start them up again.

Sadly, this story of discovering a new species only to lose them a few years later is all too common ⁽⁹⁾, and with them we lose their untold stories.

What you can do

Support initiatives to inspire the next generation of herpetologists (scientists that specialise in amphibian and reptiles) including our conservation and education work .

Even our “common” species are declining in some areas. If nothing is done now, they may not be there in the future. Use our Dragon Finder app to report any of your amphibian and reptile sightings (applicable to species found in the UK). So that the location of your local populations are recorded.

References

(1) Meyer, E.; Newell, D.; Hines, H.; May, S.; Hero, J.; Clarke, J.; Lemckert, F. (2004). Rheobatrachus silus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. Downloaded on 01 October 2013.

(2) IUCN (2013). IUCN Red List of Threatened Species. Version 2013.1. www.iucnredlist.org Downloaded on 01 October 2013.

(3) Hines, H. (2002) Recovery plan for Stream Frogs of South-east Queensland 2001-2005. Environmental Protection Agency, Queensland, Australia. Downloaded on 01 October 2013.

(4) Tyler, M.J. and Davies, M. 1983. The gastric brooding frog. M.J. Tyler, eds., Croom Helm, London.

(5) Hero, J. and Morrison, C. (2004). Frog declines in Australia: global implications. Herpetological Journal 14:175-186.

(6) Tyler, M.J. and Carter, D.B. (1982). Oral birth of the young of the gastric-brooding frog Rheobatrachus silus. Animal Behaviour 29:280-282.

(7) Tyler, M.J.; Shearman, D.J.C.; Franco, R.; O’Brien, P.; Seamark, R.F.; Kelly, R. (1983). Inhabitaion of gastric acid secretion in the Gastric Brooding Frog, Rheobatrachus silus. Science 220:609-610.

(8) Hero, J.; McDonald, K.; Alford, R.; Cunningham, M.; Retallick, R. (2004). Rheobatrachus vitellinus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1.  Downloaded on 01 October 2013.

(9) Wake, D.B. and Vredenburg, V.T. (2008). Are we in the midst of the sixth mass extinction? A view from the world of amphibians. Proceedings from the National Academy of Science 105:11466-11473.