Tell them to look up how ducks, mate.

Humans are part of nature.

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

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.

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

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)

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.

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.

Insects are the most brutal species. Parasitic wasps are literally top 10 worst ways to die.