Why Elephants Have Trunks

Posted by admin on June 1, 2012  |   No Comments »
Packy’s huge trunk. Credit: Oregon Zoo

Packy’s huge trunk. Credit: Oregon Zoo

Evolving larger takes ten times more generations than becoming smaller, according to research published this week in Proceedings of the National Academy of Sciences. Biologists estimate elephant-sized mammal requires 10 million generations to evolve from rabbit-sized one.

This new research adds to our knowledge about why elephants have trunks. While children’s stories offer different explanations, scientists remain firm in their conviction that elephants evolved from much smaller animals possibly with smaller trunks—similar to a tapir.

Trunks evolved to stay in contact with ground

As the elephant ancestors’ size increased, their trunks evolved to stay in contact with the ground. In a 10-13 foot tall animal, either the neck has to be long enough to, or there needs to be another approach. Because elephants’ teeth and jaws became massive to be equal to the task of grinding the branches and thorns of acacia trees, their heads were too heavy to be supported by anything but a short, thick neck.

Snorkel?

An alternative theory, still under consideration and awaiting more study of fossil evidence, is that elephants may be related to manatees and dugongs. In other words, a common ancestor of manatees and elephants could have used a trunk as a snorkel.

From 55 million years of evolutionary data, we know that two or three species remain of the 164 elephant relations that lived in the past. The extinct forms ranged from deserts to mountaintops, on every continent except Australia and Antarctica. What scientists are looking through the fossil record for is more information on how and when elephants developed their infrasonic call. Most of this research is based on inferences from comparisons of extinct” proboscidean”  structures and our living elephant forms.
p>From 55 million years of evolutionary data, we know that two or three species remain of the 164 elephant relations that lived in the past. The extinct forms ranged from deserts to mountaintops, on every continent except Australia and Antarctica. What scientists are looking through the fossil record for is more information on how and when elephants developed their infrasonic call. Most of this research is based on inferences from comparisons of extinct” proboscidean”  structures and our living elephant forms.

Riddle
Why do elephants have trunks?…..They have too much luggage for a glove compartment!

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