Tell them to look up how ducks, mate.

Humans are part of nature.

Some examples in no particular order:

• Cowbirds lay eggs in other birds’ nests, and if the other bird kicks their eggs out, the cowbird will come back and destroy the nest.

• You’ve probably heard of female black widows eating the male after mating, but did you know that this is so common among spiders that the males of some species are literally hardwired to automatically die during or after mating? Makes the whole process easier and prevents the male from getting away.

• Toxoplasmosis mind controls mice and makes them seek out cats so they get eaten and the parasite can move on to the cat.

• The hyena birth canal. If you think human childbirth is excruciating… you’d be right actually, we’re pretty high up there on the list of animals with the worst birthing experiences, but hyenas have it even worse.

• There’s a parasite that goes into a fish’s mouth, eats its tongue, and attaches itself to where the tongue used to be and essentially becomes the fish’s tongue.

• Hamsters eat some of their own offspring if they have too many to ensure they have enough resources to properly care for the rest.

• Baby sharks try to kill and eat each other in the mother’s uterus.

Predators eating prey alive, like lions eating bison from their bellies first.

Here’s some I know:

• Dolphins rape other dolphins https://theconversation.com/dolphin-sexual-politics-gets-the-tabloid-treatment-6063
• Praying mantis females often eat the head of males they have sex with. Some spiders do that too, like the appropriately named black widow spider. https://en.m.wikipedia.org/wiki/Sexual_cannibalism
• Mass extinctions have occurred in the past, way before humans existed https://en.m.wikipedia.org/wiki/List_of_extinction_events
• Genetic mutations often lead to inviable offspring or awful conditions (I don’t know specific examples off the top of my head)
• Parasites can take control of insects and lead them to drown (also don’t know examples off the top of my head)

Dead and desiccated bodies around a body of water that has dried up. Fish, antelope, wildebeest, etc.

Pigs. Pigs take one generation to revert to feral state and are naturally pack hunting, intelligent, omnivores. Right now Texas and Florida is dealing with cases of hogs pulling apart horses to eat. There are cases where the hogs followed hunters home and trashed the place in retaliation.

It’s a testament to our hubris that we’ve kept pigs and dogs for so long. Dogs won’t recover, but pigs only need a year to come back for blood.

Some species of ants invade neighboring colonies and carry away larva to work as slaves.

https://en.wikipedia.org/wiki/Slave-making_ant

The insect world is a tiny nightmarish hellscape of armor, weapons, and sudden death.

Also, evolution isn’t maximally efficient, it’s just barely efficient enough. Eyes are a janky, often low-fi is good enough, affair. 99.9% of species that have ever existed are extinct. 99.9999999999% of species alive today do the bare friggin’ minimum to throw DNA into either the wind or a hole and maaaaybe do nothing more than reproduce.

The Helicoprion existed.

Jellyfish. WTF?

There have been a few significant mega-extinction events which have wiped out nearly every living thing on this earth.

Cordyceps fungus. Prion diseases like Chronic Wasting Disease.

Both are horrible

otters. baby otters. otters offering baby otters to be eaten first by predators.

Any documentary that talks about the life of insects and smaller animals is a horror film.

Beavers fuck up habitats and ecosystems about as much as humans used to before factories, which accelerated what we could fuck up. Beavers wreck shit up. Sometimes elephants do too, for that matter. And let’s be clear, the modifications these animals cause can have overall eventual benefits for an ecosystem, but they change the ecosystem extensively over a huge area, and any benefits you can ascribe to their actions could as easily be applied to human ecosystem modification too. “Oh yeah, the forest is completely gone, but now there’s new homes for different kinds of creatures that couldn’t live there before.” This sentence applies 100% to elephants, beavers, and yes, humans.

Some animals change their environment. We are one of them. Our tool use and brains allow us to do so on a pretty wide scale, but the destruction the elephants caused was pretty darn huge too. Humans also have the capacity to do with intention towards actively helping an ecosystem… elephants don’t have the ability for that kind of intentionality.

Of course, humans are also fully capable of acting without that intentionality too. It is pure coincidence that new ecosystems appear in the wake of elephant or beaver devastation— they weren’t actively trying to help other animals, they just wanted what they wanted. Our destruction can also have unintentional new ecosystems arise in our wake— the problem is that often we don’t LIKE the new ecosystems (bacteria and viruses, for example), and we often DO LIKE the stuff we destroyed.

But it’s not really different from what animals do. Because we aren’t separate from nature, we are nature. If we are bad, nature is bad. If nature is good, we are good. But this kind of binary thinking is too simplistic, life is more complicated than that, and we as humans have an ability to make value judgements and moral distinctions in a way that most animals cannot. We shouldn’t use that power in such a reductive way.

First thing that comes to mind is reproduction/labor/birth. Especially ducks, otters, hyenas in no particular order of brutality. Add in spiders, preying mantis, angler fish.