I am working on an extraterrestrial class of tetrapod-like organisms. To give them an evolutionary advantage, I am considering biological hydraulics to supplement the muscles in the hind legs. Eventually I may ask about more mechanisms, but currently, I am investigating whether or not this would even be worth the energy.
The class comes in a similar size range to land mammals, with the smallest weighing about two grams and the largest at around twenty tonnes. Of course in some species, the hydraulics could have become an obsolete trait. Some things the entire order has in common are:
- Four chambered heart
- Warm blood
- A closed circulatory and a separate closed lymphatic-like system
- A two chambered lymphatic heart-like organ below the true heart to pump lymph
- Small, rigid lungs with a unidirectional pattern of breathing
- Four respiratory airsacs
- Endoskeleton with four limbs, a skull, and one to two tails
The basic design is the circulatory or lymphatic system functioning as storage for hydraulic fluid. The blood or lymph will then be forced via muscle contractions into closed chambers in the thigh to push the limb when required. I am also considering using a separate fluid stored in the abdomen, but less so because of the loss of space to other organs.
Would hydraulics systems help the creatures survive, or would they be a waste of energy?