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Species of the week: Tenrecs

Posted by on November 23, 2012

The Greater Hedgehog Tenrec (Setifer setosus), Museum of Comparative Zoology, HarvardGuest blog by Sive Finlay, a PhD student from Trinity College Dublin

Tenrecs are one of the most interesting and fascinating mammal groups yet many people have never heard of them. They are one of only four mammalian groups to have colonised Madagascar, a land filled with evolutionary curiosities.

Tenrecs are a striking example of convergent evolution. From a single colonising ancestor, tenrecs have evolved into incredibly diverse species which resemble moles, shrews, hedgehogs and even otters! Contrary to appearances, tenrecs’ closest relatives are actually the golden moles and elephant shrews (Chrysochloridae).

However, physical convergences are so strong that early taxonomists didn’t recognise tenrecs as a separate family, an easy mistake to make when you look at this picture of the Greater Hedgehog Tenrec (Setifer setosus) in the Museum of Comparative Zoology at Harvard University.

In addition to being great species for studying convergent evolution, the tenrec family includes a whole host of quirky traits. For example, the common tenrec (Tenrec ecaudatus), an animal which is only around 30 cm and 2kg, holds the record for the largest litter size of any mammal at an astounding 32 babies!

The common tenrec (Tenrec ecaudatus), Museum of Comparative Zoology, Harvard

My personal favourite tenrec oddity is the unusual means of communication found in the lowland streaked tenrecs (Hemicentetes semispinosus).  These cute critters are covered in spiny quills, a special set of which are used as a stridulating organ. Reminiscent of grasshoppers or crickets and uniquely among mammals, these tenrecs rub the quills together to produce sound which then allows them to keep in contact with their family group. This clip from the David Attenborough BBC series on Madagascar shows the stridulating tenrecs in action.

In short, tenrecs are an awesome family filled with evolutionary oddities yet they remain relatively understudied and poorly understood.

In my PhD work, I’m particularly interested in measuring the extent of convergent evolution in tenrecs and figuring out the reasons why they have evolved to be so similar to unrelated species. I’m also intrigued by early behavioural experiments which showed that 3 species of tenrec use echolocation. I want to test whether other tenrec species also echolocate and hopefully link this behavioural convergence to genetic similarities in “echolocating genes” which are conserved in whales and bats.

In the meantime, a charming children’s book, Tenrec’s Twigs gives the perfect excuse for some light, PhD-related extra reading!

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