Animals, including human animals, are enormously influenced by both nature, inherited traits, and nurture, environmental influences. Neither exists independent of the other, so both together drive all animal behavior and traits.
Often the dualistic view that everything is one thing or another is simplistic, and a hazard to true understanding. There is both nature and nurture affecting all organisms, all the time. A constant overlap between them is more significant than any differences between them. Still, there are a few differences between nature and nurture, despite the fact that they are never separate from one another. The genes people (and all organisms) have are primarily determined by nature, or inherited traits. The genes react within a climate, temperature, outside influences and timed genetic reactions, throughout lifetimes. So,they are affected by nurture, or the environment.
This means that all organisms have some genetic traits that are going to be “switched” on and off depending upon environment and its influences. In the case of non human animals behavior is more impacted by environment in those situations which could be deemed unnatural. Places such as factory farms, or any conditions which restrict range, will greatly impact natural tendencies of behavior. A big cat for example, when caged, or limited to any small space, will quickly become pathologically neurotic, depressed and sometimes aggressive. Most people have observed the pacing neurosis, and anxiety expressed by any large animal in a restricted cage.
Humans too, behave differently when caged as well. This is well documented by prison life. Any organism, if restricted from naturally evolved behaviors, will be completely different in any controlled lab environment, or otherwise restricted location. This makes it very hard for reproducible results to be created when comparing how natural animals behave as compared to kept animals. However that still does not have much bearing upon where nurture and nature overlap. For example, a person who has no freckles at birth, will only get them when exposed to the sun. In a tropical climate with high UV, a person with red hair and fair skin will have inherent genetic predisposition to burn, freckle and/or be sensitive to exposure. A person who lives in a cave, or seldom ventures outdoors, as it may be freezing, will still have the genes, but not the same result.
Because of their more instinctively driven nature, the most subtle differences between nature and nurture among non human animals is more difficult to verify. Do zebras behave differently around predators with human tourists around? Without intrusive research, this kind of question is very difficult to know for certain. What can be known for certain is that differing features of nature and nurture do exist.
All animals, including human animals, evolved with both nature and nurture affecting them from the moment of conception. There is considerable overlap, even in that the uterus is of course affected by environmental conditions. A few examples (in human animals) are smoking, malnutrition, drugs, climate and much more. Examining identical twins is fascinating because they share complete genetic blueprints. They often share traits and even behaviors despite sometimes being raised separately. However, if both are born swimmers and one lives in the tropics and the other lives near the north pole, they will not both likely be avid outdoor divers. Twins are essentially clones. They are from the same divided ovum and share genetic traits just as a cloned animal cultured from the existing DNA in any animals cells will share.
Studying the differences between environmental influences and inherent tendencies is fascinating. Trying to account for each subtle difference is often difficult and may not always be possible. Still animals, both human and non human, have extraordinary knowledge to teach us through countless varying behaviors and observable traits.