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.
Find out about this hidden order of amphibians from our Croaking Science Volunteer Hannah Graves.
There are three groups of animals within the amphibians, known as “orders”. We’ve all heard of frogs and toads, the Anura, and salamanders and newts, the Caudata, but what about the third group? These are caecilians, the Gymnophiona, a group which contains just 3% of the amphibian species (1).
Caecilians can be found across most of the tropics except Madagascar and Australia (2). The majority of caecilians are fossorial, meaning they live underground. This type of lifestyle gives caecilians many of their defining characters. They have elongated, limbless bodies, and many are also tailless, allowing them to move through the soil more easily. The skulls are highly ossified, also to aid burrowing. The eyes are covered by skin or bone so they can only sense light or dark, but more refined sight isn’t needed for a life underground (2).
Most adult caecilians feed on soil macro-invertebrates such as earthworms, termites and ants. Some may also be partly detritivorous, meaning they eat dead plant or animal matter (3). The young, however, have a slightly more gruesome diet. After giving birth, the mother remains in a burrow with her young for some time. The young feed on liquid secretions from the mother, similar to young mammals feeding on milk from their mothers.
But caecilians also eat the skin of their mother. The top layer of skin is very fatty and therefore high in energy, and the young have specialised teeth to allow them to peel off the skin. This happens every few days to allow the mother to replenish this fatty layer. In some species the young also eat fatty layers from the mother’s insides before they are born! (4).
There is still much we don’t know about caecilians due to their fossorial nature, particularly surrounding their behaviour and life histories. For example, some scientists believe caecilians may have complex social behaviours due to specimens being found with bite scars from other caecilians and some species having sexual dimorphisms – differences between males and females. There may also be more species we haven’t discovered yet (2).
What can you do to help?
If you’ve just stated out on your journey of discovery into the world of reptiles and amphibians visit our species pages to find out what you may have in your garden or local area.
Use our dragon finder app to report any of your sightings of the species that you find (applicable to species found in the UK).
1. AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2013. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. Downloaded on 28 October 2013.
2. Pough, F.H.; Andrews, R.M.; Cadle, J.E.; Crump, M.L.; Savitzky, A.H.; Wells, K.D. (2001) Herpetology 2nd Ed. Prentice Hall Inc., New Jersey.
3. Gaborieau, O.; Measey, G.J. (2004) Termitivore or detritivore? A quantitative investigation into the diet of East African caecilian Boulengerula taitanus. Animal Biology 54:45-56.
4. Wilkinson, M.; Kupfer, A.; Marques-Porto, R.; Jeffkins, H.; Antoniazzi, M.M.; Jared, C. (2008) One hundred million years of skin feeding? Extended parental care in a neotropical caecilian. Biology Letters. 4:358-361.