The Sloth and the Greenland Shark

A parable on slowness in three parts, from someone who can't sit still

I. To become a world

When I was around four or five years old, one of my favorite pastimes was memorizing dinosaurs — their names, how they looked, their size… When I wasn’t burying myself in a dinosaur book, I regaled (or annoyed) my parents with my newfound knowledge, including wild gestures and sound effects, obviously.

Then, I learned what happened after the meteor strike that heralded the end of the ‘terrible lizards’. The subsequent age of mammals doesn’t have the same reputation as dinosaur time, but it’s remarkable in its own right. Massive mammoths, sabretooth tigers, woolly rhinos, and giant sloths, oh my.

And then, humanity.

Many mega mammals did not survive the rise of modern humans due to a combination of direct hunting and indirect ecosystem effects. Among the fallen giants we find the large ground sloths of the family Megatheriidaei. Twenty-foot, four-ton chonks that wandered South American grass- and woodlands. They did not survive humanity’s arrival but their smaller cousins did. Today, six sloth species hang from South America’s rainforest trees. As their name implies, they are famously slow. That doesn’t sound like a brilliant strategy. In nature, unless you’re armored, poisonous, or big, being slow is an invitation to get eaten.

Unless you turn your slowness into a strength. The sloth’s slowness is its stealth. The predators they should be most worried about - jaguars, ocelots, and eagles - are visual hunters. Sloths move at a pace that renders them nearly invisible in the canopy. They don’t move unless there is good reason to; every motion is suffused with intent. It also helps that sloths have unique grooves and cracks in their hairs where algae grow. The greenish tint of sloth fur provides extra camouflage and the sloths sometimes eat the algae as a nutritious snack. There’s more. The algae also feed a species of moth¹ that lives exclusively in sloth fur. More? Okay, some fungi that grow in sloth fur have anti-bacterial and anti-cancer properties.

As a result of their slow lifestyle, sloths have a metabolic rate that is about half of what we would expect for their body size — they have the lowest metabolic rate of any non-hibernating mammal. This allows them to hang from their branch, slowly munch on leaves, and spend their entire lives in a single tree. They only descend for a weekly pooping ritual. Because of their extremely gentle motions, the sloths don’t disturb the ecosystem that grows in their fur.

In slowness, the sloth becomes a self-contained world that moves with intent.

II. Deep growth

We leave the rainforest and travel to deep, dark Arctic waters. Something lurks there, something large and slow.

The Greenland shark (or Somniosus microcephalus for friends) is one of the largest shark species with individuals recorded at close to 6.4m (21ft). Considering its body size, it’s also the fish with the lowest known relative swim speed. Its diet is varied and includes various fish and seals, but we still don’t know how these slow giants manage to catch their agile prey. Some researchers suggest that the sharks sneak up on their prey as it is sleeping², but we don’t have any direct evidence of that.

Hi, just checking whether you were asleep. Why? Oh, no reason… (Wikimedia Commons, Hemming1952)

Why is this shark so slow? The Greenland shark prefers deep, cold waters (−0.6 to 12°C or 31 to 54°F) and fish are ectothermic — their activity and metabolism depend on the environment’s temperature. Like the sloth, the Greenland shark has a very slow metabolism, which tends to correlate with a long lifespan. And indeed, these sharks are the longest-lived vertebrates we know. Based on growth rates and radiocarbon dating of eye lenses, it’s clear that they can live for centuries, with estimates settling around 400-500 years, plus or minus a century or so. They probably sexually mature around 150 years of age and pregnancies last somewhere between 8 and 18 years³!

In contrast to mammals, many fish (including sharks) grow indeterminately — they grow throughout their lives, even if the rate of growth might change. Add an extreme lifespan, and you’ll end up with an icy ocean giant like the Greenland shark.

In slowness, the Greenland shark outlasts and outgrows all those around it.

III. Learning slowly

This would not be a parable without a lesson.

The lesson is not that speed is detrimental. Sometimes, you need to sprint, pivot fast, and seize an opportunity before it passes.

The lesson is that slowness is not always detrimental either. It’s a hard lesson for me: I loathe the feeling of sitting still⁴ — which is an odd thing to write for someone who is often paralyzed by overthinking everything. It does not surprise me that abyss diver and writer Cesare Pavese has a pithy quote for this affliction of existential restlessness,

The slowness of time, for a man who knows nothing will happen, is brutal.

Gloomy. The sloth and the Greenland shark still move, though. Especially in the shark’s case, slowness does not preclude movement. The key, the challenge, is finding the balance between fast and slow, in both mind and motion. Who better to articulate that lesson than legendary Japanese swordsman and strategist Miyamoto Musashi, who, in the Book of Wind (part four of his Book of Five Rings), wrote,

Speed is not part of the true Way of strategy. Speed implies that things seem fast or slow, according to whether or not they are in rhythm. Whatever the Way, the master of strategy does not appear fast.

Once upon a time, a limited, commercial, and probably unreliable genetic test told me I was (slightly) more predisposed to speed than endurance. I think this extends beyond sports. I can be patient to the point of stubbornness when it has a purpose. But slowness without a purpose? I can barely sit still for an hour before bouncing around a room⁵. I am a creature of restless currents beneath a calm surface.

I am trying (failing, but trying) to appreciate slowness.

Like the sloth, slowness will let me become a world of ideas and interests that moves with intent until it has found a tree that is just right. Like the Greenland shark, slowness will let me grow without limit. Everyone is obsessed with growing up; I will grow on. Being ‘grown up’ implies the end of a stage; a forced sprint followed by stasis. I refuse to put an endpoint on my growth, even if that slows me down. Mid-to-late thirties? Barely out of diapers for a Greenland shark. Especially in our rushed existence, this is a lesson worth remembering.

I vibrate with a need for speed, an unquenchable desire to become [question mark], even though I’ve never been on a ‘30 under 30’ list. In a world where everything is a race, I can’t help but get ready in the starting blocks and I am not alone. We are collectively incentivized to race in our hamster wheels to keep things running⁶. What if, like the sloth and Greenland shark, we sidestep the race that burns everyone out? What if we decide to move at our own pace? Perhaps Hollywood icon Mae West said it best,

Anything worth doing is worth doing slowly.

I’m not a sloth or a Greenland shark, but I can try to find moments of stillness and appreciate them for the perspective they bring.

Slowly.

Quickly, click all the buttons and hearts! Hurry, the algorithm is unforgiving.

(If you’re a fellow newsletter writer and think your readers might appreciate my writing, you can recommend Subtle Sparks, if you are so inclined…)

1. Imaginatively called the sloth moth.

2. You’re welcome for that nightmare fuel. More likely, Greenland sharks are scavengers.

3. Nightmare fuel, the sequel.

4. Standing desks for the win. At least I can bounce in place while working and writing this way.

5. You can imagine how meditation or mindfulness works out for me…

6. Two running metaphors jumbled together in one sentence? In a post on slowness? You’re welcome.