# What animals would be quickest to adapt to a low gravity world? [closed]

Aliens have discovered a new planet in its Goldilocks zone that (other than gravity) is the same in every way to Earth. They wish to bring Earth animals into the planet to create their own ecosystem test, but there exists a problem, this new planet (named Terra) has a gravity 72% that of Earth. The life that currently exists on Terra is comparable to very basic plants and animals but it is very early life. They have enlisted their greatest minds to figure out what animals to choose. What Earthen animals would be to quickest able to adapt to this new low gravity world?

• There are quite a few animals on Earth. This seems really broad/possibly opinion-based. The answer would also depend on what native species are present on the planet in question which is not included in the question (and I doubt could reasonably be included within 80,000 characters if it is just like Earth.). – JDSweetBeat May 10 '16 at 18:05
• In addition to @DJMethaneMan's comments, I think it would be good if you were to clarify what the intent is in bringing the animals to the planet. Are your aliens just trying to bring domesticated animals for food/company or are they intending to release the animals into the wild in order to create an entire animal ecosystem? The latter has implications on inclusion of bugs/pest species. Is the local flora/fauna comparable/compatible with Earth animals? – WhataTiberius May 10 '16 at 18:29
• I agree with the other comments. We need some criteria to judge, otherwise "best" is just an opinion. – ChronoD May 10 '16 at 19:28
• has a gravity 72% that of Earth. - 99% of all/any existing now. – MolbOrg May 10 '16 at 19:57

I would say almost any animal.

smaller animals are "less susceptible" to gravity changes since being smaller they have a lower volume/surface ratio, so with a 0.72 g they would barely notice.

water dwelling animals would also barely notice since they live inside water where buoyancy almost negate their weight.

bigger animals would indeed notice and with time they would be subject to some changes. However an adult elephant that weights 7000 Kg on Earth would be about 5000 Kg on Terra; not a very big difference. They are going to be ok.

• I'm not sure even larger, land-based animals would notice very much, given that the gravity is reduced compared to Earth. It would be a potentially different matter if the gravity was instead increased to e.g. 1.39g (which is the inverse of 0.72; $\frac{1}{0.72} \approx 1.39$). – a CVn May 10 '16 at 21:20

Birds. There entire existence depends on them overcoming gravity. In this new existence you've actually made their job easier because now gravity is weaker so it takes less effort for them to overcome it. Depending on how low your gravity was birds that have wings but aren't able to fly such as chickens would it be able to gain the ability. Assuming there were no other changes just a slight decrease in gravity and I think birds with not only adapt and survived but I think they would thrive.

• I don't think so. Flightless birds are not handicapped, it is an adaptation. Chickens are a poor example in my opinion since there are species here on Earth that can fly, plus a 2,6 Kg chicken would weight over 1,8 Kg on Terra, still a considerable amount, plus the air around them is also lighter. Maybe the lighter will become capable of some short flight but it won't change that much. – SilverCookies May 10 '16 at 18:35
• @SilverCookies admittedly they probably will not be able to fly like a hawk or an eagle. But I've seen chickens who are capable of short flights. Presumably If gravity was less they could extend those short flights into longer flights. I may never be able to fly continuously like an eagle, but they would still be able to do more then what they can do now. – Bryan McClure May 10 '16 at 18:39