Evolution: development of the elephant trunk (Introduction)

by David Turell , Thursday, October 25, 2018, 18:38 (2008 days ago) @ David Turell

Obviously if tusks get so long that the mouth cannot reach the ground, then a trunk needs to be developed to get food into the mouth, so the elephant trunk is a marvelous structure, but the issue, as in whales, is why bother to cause the problem in the first place?:

https://cosmosmagazine.com/biology/elephant-trunks-derive-power-and-finesse-by-simulati...

"Researchers find that an elephant’s trunk forms a kind of joint to pick up small pieces of food.

"A team of researchers led by Jianing Wu at the Georgia Institute of Technology, Georgia, USA, videoed an African elephant (Loxodonta africana) eating small pieces of food and measured the force its trunk exerted throughout the exercise. They found that the animal swept the food into piles and then formed a joint to pick up as much as possible at once.

“'Forming joints may help reduce the energy required to reach for and grab food items, a task they perform for 18 hours every day,” the researchers write in the Journal of the Royal Society Interface.

***

"Wu and colleagues found that elephants form a sort of joint at the trunk so it could clamp several bits together.

“'Although the elephant trunk lacks bones, the formation of a joint mimics a common vertebrate strategy to reach out and grab objects,” the researchers note.

"Joints allow structures such as human limbs degrees of freedom, allowing them to reach a greater range of points in space. They also can provide leverage.

“This is why appendages without bones, such as the elephant trunk and octopus arm, have both demonstrated the formation of joints,” the researchers write.

“'The octopus forms a joint like the elbow only when retrieving food. Our study shows that the use of joints might be more common than once thought.”

***

“'Such researchers have turned to snakes, octopus and elephants for inspiration. However, even among these animals, the elephant stands out because the trunk can apply the greatest forces.”
Indeed, the elephant’s trunk is the largest hydrostat – a type of boneless muscular organ – on land, weighing 150 kilograms. That weight accounts for some of the force it can exert.

“'Wild elephants may still apply the strategies we observed if they need to press downward with their trunk while feeding,” the authors conclude.

“'To remove the bark from a tree, vertical forces are required, and its possible the elephant may form joints for this task. Now that we have observed the formation of joints, future work will determine how often elephants use this strategy.'”

Comment: I thought in theory evolution was to seek the best way to survive. then as I've noted why bother with this degree of complexity?

To see elephant evolution see this site:

http://www.himandus.net/elefunteria/library/science+nature/evolution.html

"Not every animal from the book is included and some are included from other sources. The book chart specifically identifies several evolutionary branches of ancestral proboscidians as unproven though widely accepted. Those are marked above with [**].

"It should be recognized that the term 'ancestral proboscidians' refers to unknown and undocumented creatures which are assumed to have existed and evolved into various proboscidians which left fossil traces."

Comment: the evolutionary history contains suppositions, a usual Darwin technique.

What they need to eat:

https://www.liveanimalslist.com/mammals/what-elephants-eat-and-drink.php

"To support its large size it needs huge amounts of food. An adult elephant eats about 150 kg (300 lb) of grass, leaves, twigs and fruit each day. Tree bark is the favourite food source of elephants. To supplement the diet, elephants will dig up earth to obtain salt and minerals. The tusks are used to churn the ground."

Comment: Wow!