While some "experts" on past lives will claim that animals do not incarnate into humans, the first two lives I recall were as a jaguar and then a dolphin. If you ascribe to the idea that we exist on this plane to perfect ourselves spiritually, then the idea that we start in a low capacity and proceed to evolve to a more perfect state is not so antithetical to a procession of births from animal to human. A human is just another kind of animal after all. Even if I did not recall being an animal, as a high functioning empath, I can tell you animals are not "dumb." Even plants have a consciousness (even rocks do). It would be better to say that animals and plants have a different kind of intelligence, different priorities, which direct their consciousness in ways we would not consider "intelligent." I don't care. Some of my best friends are trees and birds.
The lives I lived as animals were nothing special. As a jaguar, I fell out of tree and broke my leg. I starved to death before it healed. As a dolphin, I lived to be fairly old and died when I could no longer reach the surface for air. But no life I have yet recalled has been completely useless. In the depths of my being, I carry qualities of these two animals.
I'm pretty close to being a pacifist now, but... I wasn't always. Like a jaguar, I had a tendency to defend my territory violently... my territory not being places or things, but people... family... my few friends. I've had to struggle to bring myself under firm control. In terms of diet, I ate steak, nearly raw, and drank the blood from the plate after (don't judge) well into my late teens. Now I'm a vegetarian. I could be very dangerous if I had a mind to be, but giving in... is dangerous. My father was a monster, and I don't want to be like my father, so I gentled myself. But it's still in me to be, not so gentle. I have a terrible temper, but at least I no longer fly into uncontrollable rages.
What I gained from my life as a dolphin is harder to pinpoint, but I would say it is a sense of peace and of... belonging. Don't get me wrong. I have never felt like I belonged with normal, decent people, but there is a kinship there that the predatory nature of both the jaguar and the dolphin leads me to defend. Dolphins, like wolves, horses, and humans (and unlike jaguars) are "herd animals" who defend their own from predators.
Either way you look at it, beneath this nerdly exterior is a dangerous predator, fiercely independent but also fiercely protective of the weak and the stragglers of the herd. Don't hurt people under my protection, and we'll get along just peachy. Dolphins after all have a loving nature to go with their status as predator. And I've trained myself to be patient and forgiving of the disappointments heaped upon me by others.