Swarms, herds, flocks, packs. When I think of animals, I tend to think of them living together in community. Bees in particular evoke images of hives — giant battalions of workers busily serving the queen, a great glistening mass I once saw slithering around the honey-laden frame held by an intrepid beekeeper friend.

Imagine my surprise, then, to learn recently of “the solitary bee.” They’re more diverse than their social honeybee and bumblebee brethren — there are 4,000 species in the U.S. alone, accounting for 98% of our total bee species. They’re also equally important pollinators.

The male solitary bee has but one function — to mate. The female gives birth, lives independently, collects pollen for her young, and then dies.

About a third of these creatures make little burrows for themselves, cavity-like tube-shaped spaces in loose masonry, window frames, garden furniture; on plants and rock crevices. The other 70% tunnel underground.

They’re quiet. They don’t attack and sting. They display an astonishing range of color, adornment and size.

They’re way less known than the social bees, but from a survey of the literature and online presence, their followers are devoted, if not obsessive.

What other animals prefer to live alone?

Contrary to its name, I learned, the hermit crab is an extrovert, prefers to live in large groups, and gets antsy when left alone for too long. Ants themselves are “eusocial,” meaning roughly, hyper social, with an advanced level of social organization in which a single female produces offspring and basically everyone else cooperates in caring for the young. No introverts there!

The “hermit” designation refers to the crab’s habit of using another creature’s shell as its home to protect its soft innards, squeezing itself into and creating a kind of “hut”: a practice I thoroughly endorse.

Most seals live in colonies but the (aptly named) monk seal is a recluse. The National Oceanic and Atmospheric Administration (NOAA) reports: “Hawaiian monk seals are mostly solitary and don't live in colonies like sea lions or other seals. But they do sometimes lie near one another — usually not close enough to make physical contact — in small groups. They usually sleep on beaches, sometimes for days at a time.”

Sounds like my family during our teenage years.

A site called “Captain Dave’s Whale Watching” explains: “Also surprising to what many may think, humpback whales do not travel in groups based on family ties. The life of rorqual whales can be lonely, and some humpback whales travel alone all year long throughout their lifetime.”

Treehugger.com lists the top eight of the world’s most solitary animals: the platypus, the polar bear, the snow leopard.

Many of these loners get together only to mate. There’s even a bird: “Unlike other sandpipers that nest on the ground, the solitary sandpiper prefers borrowing old songbird nests high in the trees. If they’re approached, these shy birds bob nervously, make high-pitched, whistle-like cries, and eventually fly away.”

The moose also likes to hang out by itself. Desert tortoises are so antisocial that the mothers lay their eggs in the ground and take off, never to return. Only 2% of their hatchlings survive.

The chuckwalla lizard spends its days sunbathing — alone. The male will attack another male who tries invading his territory. What a curmudgeon!

Treehugger notes that advantages to the solitary animal life include “economic defensibility” (you don’t have to share), “access to limited resources” (you don’t have to share), and “less hunting” (you don’t have to work so hard and you don’t have to share).

The considerations sound selfish laid out like that, but some of us are just made that way. How do we know that hidden away in their lairs, caves, nests, and rocky outcrops, these creatures aren’t mulling over the mystery of existence? Or giving thanks? Or praying?

In “Encounters at the End of the World,” a 2007 documentary on Antarctica by Werner Herzog, there’s a clip about a bird who seemingly inexplicably peels off from the crowd (search “Nihilist Penguin” on YouTube).

Instead of waddling to the open-water feeding grounds with the rest of the colony, he heads straight in the opposite direction for the mountains, a journey of possibly thousands of kilometers that will end in certain death.

“Is there such a thing as insanity among penguins?” Herzog asks marine biologist David Ainley. “Could they just go crazy because they’ve had enough of their colony?”

“They do get disoriented,” Ainley replies. “They end up in places they shouldn’t be, a long way from the ocean.” Even if they caught the rogue penguin and brought him back to the colony he would immediately head right back to the mountains, Ainley continues.

So the rule is for humans not to disturb or hold up the penguin. Stand still, and let him go on his way.

I don’t want to take my anthropomorphizing too far. But watching that lone penguin stolidly set off for the “interior of the vast continent,” as Herzog calls it, I thought of Dietrich Bonhoeffer (1906-1945), the German theologian who was executed for his opposition to Hitler’s euthanasia program and genocidal persecution of the Jews.

“When Christ calls a man,” he wrote in “The Cost of Discipleship,” “he bids him come and die.”