10 Rare Animals, And Why Each One Is Rare

A small porpoise in the northern Gulf of California, and the most endangered marine mammal in the world. Around ten remain.

It is not hunted. It drowns in illegal gillnets set for another fish, the totoaba, whose swim bladder sells for very high prices in illegal markets. The vaquita is dying as a side effect of a trade in something else entirely, which makes it the clearest case anywhere of how lethal bycatch alone can be.

A crocodilian with a snout barely wider than the bone inside it, lined with over a hundred interlocking teeth, which lets it sweep its jaws sideways through water faster than any crocodile could.

It is harmless to people and eats almost nothing but fish. Most of the world’s breeding gharials now live in a single Indian river, the Chambal.

Madagascar’s largest living lemur, and the only mammal besides humans known to sing in categorical rhythm, established by an analysis of twelve years of recordings.

It is Critically Endangered, and there is no safety net: no indri has ever survived long in captivity, so it cannot be bred as insurance against losing the wild population.

The last wild Spix’s macaw disappeared from Brazilian dry forest in 2000. The species survived only in private collections, mostly belonging to the collectors whose trade had emptied the forest.

Those birds were tracked down, bred in Germany and Qatar, and released back into the same caatinga in June 2022. Some have bred in the wild since. It is one of very few cases of a bird going extinct in the wild and being put back.

Not rare in numbers, with 60,000 to 100,000 alive, but rare in a way nothing else is: the tuatara is the only surviving member of an order of reptiles that split from lizards and snakes about 250 million years ago, before the first dinosaur.

Every other species in that order is extinct. It survives on around 30 New Zealand islands, and what nearly finished it was rats arriving on boats.

A Madagascan tortoise with a few hundred left, and a shell so prized by collectors that conservationists deliberately engrave the shells of wild animals to destroy their black-market value.

That is an unusual measure, and a fair indication of how severe the collection pressure is.

There were well over a million breeding pairs of this penguin on the coast of South Africa and Namibia a century ago. There are now a few thousand, and it was reclassified as Critically Endangered in 2024.

It is on this list as a warning rather than a curiosity. This is what a common animal becoming rare looks like, and it happened within living memory.

A spider that lives in a handful of lava tubes on one Hawaiian island and has lost its eyes entirely, because in permanent darkness eyes cost energy and return nothing.

Its entire world is a few caves. Rarity of this kind is about range rather than numbers, and it is the most fragile kind there is.

The only seal living exclusively in fresh water, found in a single Siberian lake over a thousand miles from any ocean.

How its ancestors got there has never been settled, which is a good reminder that the natural world still contains straightforward questions nobody can answer.

The Gila monster is not endangered, but almost nobody encounters one, because it spends around 95 percent of its life underground and eats only five to ten meals a year.

It earns a place here for what came out of it. A compound in its saliva lasts hours where the equivalent human hormone lasts about two minutes, and it became exenatide, approved in 2005, opening the GLP-1 class of diabetes drugs now used by millions.

Four of these ten are rare because of something specific and fixable: nets, collection, introduced rats, a single unprotected river. Not one of them is rare because it was poorly designed or outcompeted naturally.

Two are recovering, and one of those came back from being extinct in the wild, which is worth holding onto.

For why rare animals cluster in the places they do, there is a companion piece on why remote places breed rare animals and then lose them.