Supersense: It's a snap for crocs

July 1, 2013
Multi-sensory organs in the skin of crocodylians are sensitive to touch, heat, cold, and the chemicals in their environment, finds research in BioMed Central's open access journal EvoDevo. Credit: Michel C Milinkovitch

Previously misunderstood multi-sensory organs in the skin of crocodylians are sensitive to touch, heat, cold, and the chemicals in their environment, finds research in BioMed Central's open access journal EvoDevo. These sensors have no equivalent in any other vertebrate.

Crocodylians, the group that includes crocodiles, gharials, alligators and caimans, have particularly tough epidermal scales consisting of keratin and bony plates for added protection. On the head, these scales are unusual because they result from cracking of the hardened skin, rather than their shape being genetically determined.

The scales have sensors known as dome pressure receptors (DPR) or Integumentary Sensory organs (ISOs) with fingertip sensitivity. Researchers from the University of Geneva investigated ISOs in Nile crocodiles (Crocodylus niloticus) and the spectacled caiman (Caiman crocodilus) to find out exactly what these micro-organs can 'see and how they are formed.'.

ISOs appear on the head of the developing caiman and crocodile embryos before the skin starts to crack and form scales. Nile crocodiles additionally develop ISOs all over their body. In both animals the ISOs contain mechano-, thermo-, and chemo-sensory receptor-channels giving them the combined ability to detect touch, heat/cold and , but not salinity. Nile crocodiles have separate salt glands on their tongues which help regulate osmolarity in hyper-saline environments.

This means that they can detect surface allowing them to quickly find prey even in the dark. The thermal sensitivity help them to maintain body temperature by moving between basking in the sun and cooling in the water, and the may help them to detect .

Prof Michel Milinkovitch, who led this study explained, "ISO sensors are remarkable because not only are they able to detect many different types of physical and chemical stimuli, but because there is no equivalent in any other vertebrates. It is this transformation of a diffuse sensory system, such as we have in our own skin, into ISO which has allowed crocodilians to evolve a highly armored yet very sensitive skin."

Explore further: Despite their thick skins, alligators and crocodiles are surprisingly touchy

More information: Crocodilians Evolved Scattered Multi-Sensory Micro-Organs, Nicolas Di-Poï and Michel C Milinkovitch, EvoDevo 2013, 4:19.

Related Stories

Nile crocodile is actually two different species

September 15, 2011

( -- Researchers from the Fordham University in New York have uncovered evidence that what the world has looked to as the iconic Nile crocodile is actually two different species of crocodile that are only distantly ...

Scientists develop sensitive skin for robots

June 29, 2011

Robots will soon be able to feel heat or gentle touching on their surfaces. Researchers at Technische Universitaet Muenchen are now producing small hexagonal plates which when joined together form a sensitive skin for "machines ...

Recommended for you

Closer look reveals tubule structure of endoplasmic reticulum

October 28, 2016

(—A team of researchers from the U.S. and the U.K. has used high-resolution imaging techniques to get a closer look at the endoplasmic reticulum (ET), a cellular organelle, and in so doing, has found that its structure ...

Computer model is 'crystal ball' for E. coli bacteria

October 28, 2016

It's difficult to make predictions, especially about the future, and even more so when they involve the reactions of living cells—huge numbers of genes, proteins and enzymes, embedded in complex pathways and feedback loops. ...

Ten months in the air without landing

October 27, 2016

Common swifts are known for their impressive aerial abilities, capturing food and nest material while in flight. Now, by attaching data loggers to the birds, researchers reporting in the Cell Press journal Current Biology ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.