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Hello.

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Well, I'm here to talk to you
about my animal muse:

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the sloth.

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(Laughter)

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I've been documenting the strange lives
of the world's slowest mammal

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for the last 10 years.

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I still remember the first time I saw one.

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I was fascinated by their freaky biology.

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I mean, what's not to love
about an animal that's born

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with a fixed grin on its face?

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(Laughter)

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And the need to hug.

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Audience: Awww.

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But sloths are massively misunderstood.

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They've been saddled with a name
that speaks of sin

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and damned for their languorous lifestyle,

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which people seem to think
has no place amongst the fittest

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in the fast-paced race for survival.

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Well, I'm here to tell you
that we've got this animal all wrong --

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and how understanding
the truth about the sloth

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may help save us and this planet
we both call home.

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I traced sloth-based slander

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back to a Spanish
conquistador called Valdés,

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who gave the first description of a sloth
in his encyclopedia of the New World.

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He said the sloth was

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"the stupidest animal
that can be found in the world ...

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I have never seen such an ugly animal
or one that is more useless."

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(Laughter)

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Tell us what you really think, Valdés.

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(Laughter)

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I'd like to have a word
about Valdés's drawing skills.

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(Laughter)

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I mean, what is that?

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(Laughter)

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I've never seen an illustration
of a sloth that's more useless.

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(Laughter)

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But I mean, on the plus side,

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he has given the sloth
a remarkably humanlike face,

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and sloths do have remarkably
humanlike faces.

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This sloth I photographed in Costa Rica,
I think looks a lot like Ringo Starr.

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(Laughter)

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But then, sloths do bear an uncanny
resemblance to the The Beatles.

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(Laughter)

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Particularly pleased
with Paul, actually, on there.

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But like The Beatles,
sloths are also extremely successful.

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They come from an ancient line of mammals,
and there were once dozens of species

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including the giant ground sloth,
which was the size of a small elephant

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and one of the only animals big enough
to eat avocado pits whole

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and disperse them.

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So ... 
(Laughter)

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Some of you have worked it out already.

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(Laughter)

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That means that without sloths,

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there might be no avocado on toast today,

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leaving hipsters everywhere
totally bereft at breakfast.

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(Laughter)

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(Applause)

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Today, there are six surviving species,
and they fall into two groups.

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You've got your Bradypus
three-toed sloths,

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they're the ones with the Beatles haircuts
and the Mona Lisa smiles.

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Then, there are the two-toed sloths.

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They look a little bit more like a cross
between a Wookiee and a pig.

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They live in the jungles
of Central and South America,

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and they're extremely prolific.

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There was a survey
that was done in the 1970s

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in a Panamanian tropical forest

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that found that sloths were the most
numerically abundant large animal.

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They took up one quarter
of the mammalian biomass.

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Now, that's an awful lot of sloths

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and suggests they're doing
something very right indeed.

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So what if, rather than deriding
the sloth for being different,

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we tried to learn from it instead?

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We humans are obsessed with speed.

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Busyness is a badge of honor,

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and convenience trumps quality
in our quest for quick.

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Our addiction to the express life
is choking us and the planet.

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We idolize animals like the cheetah,
the "Ferrari of the animal kingdom,"

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capable of doing naught to 60
in three seconds flat.

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Well, so what?

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(Laughter)

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(Applause)

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So what?

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The sloth, on the other hand,

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can reach a leisurely 17 feet a minute

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with the wind behind it.

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(Laughter)

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But being fast is costly.

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The cheetah is speedy,
but at the expense of strength.

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They can't risk getting in a fight,

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so they lose one in nine kills
to tougher predators like hyenas.

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No wonder they're laughing.

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(Laughter)

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The sloth, on the other hand,

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has taken a more stealthy
approach to dinner.

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They survive by capturing and consuming

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static leaves.

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(Laughter)

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But you see, leaves don't want
to be eaten any more than antelope do,

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so they're loaded full of toxins
and very hard to digest.

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So in order to consume them,

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the sloth has also
had to become an athlete --

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a digesting athlete.

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(Laughter)

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The sloth's secret weapon
is a four-chambered stomach

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and plenty of time.

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They have the slowest
digestion rate of any mammal.

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And it can take up to a month
to process a single leaf,

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which gives their liver plenty of time
to process those toxins.

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So, sloths aren't lazy.

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No, they're busy.

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Digesting.

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(Laughter)

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Yeah, really busy.

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(Laughter)

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Hard at work, that sloth,
very hard at work.

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And of course, leaves
have little calorific value,

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so sloths have evolved to spend
as little energy as possible.

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They do about 10 percent of the work
of a similar-sized mammal

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and survive on as little
as 100 calories a day,

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thanks to some ingenious adaptations.

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The Bradypus, three-toed sloths,

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they've got more neck bones
than any other mammal,

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even a giraffe.

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Which means they can turn their head
through 270 degrees

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and graze all around them,

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without having to actually bother
with the effort of moving their body.

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(Laughter)

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It also means that they are
surprisingly good swimmers.

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Sloths can bob along in water

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three times faster
than they can move on land,

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kept afloat by ...

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trapped wind.

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(Laughter)

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So --

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(Laughter)

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sloths are the only mammal that we know of
that don't do flatulence.

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When they need to expel gas,

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it's actually reabsorbed
into their bloodstream

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and expelled orally
as a sort of mouth fart.

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(Laughter)

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Turning their lives upside down
saves further energy.

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They have about half the skeletal muscle
of a terrestrial mammal.

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They don't really have so many
of the extensor muscles

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that are the weight-bearing muscles;

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instead, they rely on retractor muscles
to pull themselves along.

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They have long, hooked claws
and a high fatigue resistance,

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so they can literally hook on and hang
like a happy, hairy hammock

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for hours on end.

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And sloths can do almost anything
in this inverted position.

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They sleep, eat and even give birth.

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Their throat and blood vessels
are uniquely adapted

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to pump blood and to swallow food
against the force of gravity.

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They have sticky bits on their ribs

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that prevent their enormous stomach
from crushing their lungs.

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And their fur grows
the opposite direction,

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so they can drip dry
after a tropical drenching.

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The only problem is,
if you turn a sloth the other way up,

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gravity removes its dignity.

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Audience: Awww.

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They can't hold themselves upright.

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And so they drag their bodies along
as if mountaineering on a flat surface.

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And I think this is why
the early explorers like Valdés

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thought so poorly of them,

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because they were observing sloths
the wrong way up and out of context.

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I've spent many happy hours
mesmerized by moving sloths.

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Their lack of muscle hasn't impeded
their strength or agility.

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Nature's zen masters of mellow
move like "Swan Lake" in slow mo --

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(Laughter)

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with the core control of a tai chi master.

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This one has fallen asleep mid-move,
which is not uncommon.

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(Laughter)

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But you're probably wondering:

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How does a dangling bag
of digesting leaves avoid being eaten?

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Good question.

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Well, this is one
of the sloth's main predators.

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It's the harpy eagle.

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It can fly at speeds
of up to 50 miles per hour,

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has talons the size of a grizzly bear's,

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razor-sharp eyesight,

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and that ring of feathers focuses sound

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so that it can hear
the slightest leaf rustle.

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The sloth, on the other hand,
has poor hearing, bad eyesight,

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and running from danger
is clearly not an option.

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No, they survive by wearing
an invisibility cloak

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worthy of Harry Potter.

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Their fur has grooves
that attract moisture

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and act as tiny hydroponic
gardens for algae,

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and they also attract
a host of invertebrates.

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So they are their own slow-moving,
miniature ecosystem.

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They become one with the trees.

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And we think that
their movements are so slow,

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they slip under the radar
of the monstrous harpy

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as it's flying about the canopy,
scanning for action.

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Sloths are stealth ninjas,

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and they rarely leave
the safety of the canopy --

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except to defecate,

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which they do about once a week
at the base of a tree.

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Now, this risky and energetic behavior
has long been a mystery,

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and there are lots of theories
as to why they do it.

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But I think they're leaving surreptitious
scented messages for potential mates.

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Because, you see, sloths are generally
silent, solitary creatures,

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except for when the female is in heat.

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She will climb to the top of a tree
and scream for sex.

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In D-sharp.

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(Laughter)

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Don't believe me?

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(Sound of sloth scream)

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D-sharp.

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This and only this note
will get the male's attention.

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It mimics the sound
of the kiskadee flycatcher.

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So the female remains covert,

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even when yodeling for sex
at the top of her lungs.

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Her clandestine booty calls
will carry for miles across the canopy,

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and males will beat
a slow path towards her.

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00:11:18,946 --> 00:11:23,239
(Laughter)

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I think scented messages in her dung
will help send Romeo up the right tree

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so that he doesn't waste precious energy
scaling the wrong one.

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Sex, by the way, is the only thing
that sloths do swiftly.

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I've seen them do it in the wild,

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and it's over and done
with in a matter of seconds.

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But then, why waste precious energy on it,

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particularly after that journey?

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(Laughter)

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Unlike other mammals,

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sloths don't also waste time maintaining
a constant warm body temperature.

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Energy from the sun is free,

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so they bask in the sun like lizards

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and wear an unusually thick coat
for the tropics to keep that heat in.

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Sloths have a freakishly low metabolism.

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And we think that this might be
one of the reasons

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that they can sometimes
recover from injuries

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that would kill most animals.

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This sloth recovered
from a double amputation,

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and I've known sloths
that have managed to survive

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even power line electrocutions.

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And we now think that a low metabolism
may well be key to surviving extinction.

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Researchers at Kansas University
who were studying mollusks

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found that a high metabolism
predicted which species of mollusk

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had gone extinct.

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Sloths have been around on this planet
in one shape or another

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for over 40 million years.

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The secret to their success
is their slothful nature.

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They are energy-saving icons.

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And I founded the Sloth
Appreciation Society

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to both promote and protect
their slow, steady, sustainable lives.

246
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I'm a pretty speedy character.

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I'm sure you've guessed.

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And the sloths have taught me
a lot about slowing down.

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And I think that the planet would benefit

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if we all took a slowly digested
leaf out of their book.

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How about we all embrace our inner sloth

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by slowing down,

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being more mindful,

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reducing wasteful convenience,

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being economical with our energy,

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recycling creatively

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and reconnecting with nature.

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Otherwise, I fear,

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it will be us humans that turn out to be

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"the stupidest animals
that can be found in the world."

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Thank you very much.

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May the sloth be with you!

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(Applause)