E is for Elephant.

The elephant is the largest land animal on Earth. The size of the elephant is the major reason why they are evolutionary successful and why they are still found today. It is thought that elephants grew big in order to out compete ruminants on the grassy savannah. To enable to eat the woody vegetation that were unable to be eaten by ruminants (because of the vegetation’s extremely low nutritional value), they had to develop a large digestive tracts and larger legs. About 2 million years ago, elephants inhabited every continent but Australia and Antarctica.

However, a large size also brings large problems. The elephant, that can weigh up to 7000kg and can stand up to 13 ft hight, has a lot of problems with overheating. Having a low surface area to volume ratio, the elephant is unable to lose a lot of its heat via its skin. This is a particular problem for elephants who live in extreme heat. One of the adaptations elephants have undergone to help mitigate this, is its enormous ears. One ear can be as big as single-sized bed sheet. Whilst the African elephants have larger ears than their Asian counterparts, both elephants have extremely thin ears. This means that the surface area to volume ratio for an elephants ear is much higher than the rest of the body, enabling them to lose heat quickly in these areas. Their ears also contain an unusually high density of capillaries and so this further helps with the removal of heat to the surroundings. The ears are such an effective heat reducing method that they have been known to lower blood temperature by 5 degrees!

The other problem with an enormous frame is with drinking. Being large means that stooping down to drink water is a high-risk strategy; leaving you open to attacks from predators. To get around this, elephants evolved a trunk. The trunk truly is a marvellous accessory. It can weigh up to 28 stone, be 7 feet long and contains more than 100 times more bones than the entire human body! It can suck up 8 pints of water, contains canine teeth inside it and can be used as an ‘arm’, hand, snorkel and a weapon. It can kill a lion with a single blow and yet it is dexterous enough to pick up a single grain of rice. If only we all had them!

Finally, the elephant, like most other mammals, tip toe when they move. Whilst not being able to run (a movement where all 4 limbs are off of the floor) it can still move rather briskly. The elephant can walk up to 15 mph and can do this with surprisingly little sound. The elephant’s feet are designed like shock absorbers. They have a layer of cartilage in their feet; between the bone and the pad (excess skin), which acts to absorb excess movement. The pad touches the ground first and traps air between itself and floor, minimising any of the sound the elephant would normally make. This means that despite weighing more than 3 tonnes, the elephant is able to move with much more grace than many accomplished robbers.

 

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