Did you know birds do not have receptors for capsaicin? They can eat any pepper and it doesn't affect them. So if you see a bird snacking on a pepper that's red or greenish-yellow, wrinkly, and has a pointy end, well ... watch out

And onions are mildly toxic to cats and dogs. There is a lot less shared responses as to what is toxic or edible across species.

Basically every flavor compound in an herb or spice we eat is a poison directed at insects, microbes, or other creatures. (much less every medicinal or psychoactive compound found in nature)

>It seems like there would be some advantage to some creatures of not aging, or having individuals who have significant longer life spans.

There is, if there were no advantage a whole lot more species would die immediately after reproduction like the octopus.

Many simpler organisms are vaguely immortal.

>It's easy to imagine a world where nature might want to keep the alpha lion around longer than the others so it can have more offspring, for example.

The utility of genetic diversity puts a lot of pressure against this.