TedTest

From the Ted Talk by Kenny Coogan: Why are sloths so slow?

Unscramble the Blue Letters

In 1796, thmoas jefefsron received a box of bones he couldn't identify. A long, sharp claw reminded him of a lion, but the arm bones suggested a larger animal, one about three meters long. Thinking it might be huge unknown species of notrh American lion, Jefferson warned explorers Lewis and Clark to keep an eye out for this mysterious predator. But Jefferson's box of bneos didn't come from a lion. They came from an extinct giant sotlh. prthiesroic ground sloths first aereappd around 35 miillon years ago. Dozens of species lived across North, crnteal and South aciemra, alongside other ancient creatures like mastodons and giant aldarolmis. Some ground sloths, like the meghycioland, were cat-sized, but many were massive. Jefferson's sloth, Megalonyx, weighed about a ton, and that was small cmaorepd to megatherium, which could reach six metric tons, as much as an elephant. They ambled through the forests and savannas using their strong arms and sharp claws to uroopt plants and climb trees, grazing on grasses, leaves, and prehistoric avocados. In fact, we might not have avocados toady if not for the giant sholts. Smaller aainlms couldn't swallow the avocado's huge seed, but the sloths could, and they spread avocado teers far and wide. Ground sloths flourished for millions of years, but around 10,000 years ago, they strated disappearing along with the Western Hemisphere's other giant mammals. Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other secpies, maybe humans, who arrived in the region around the time most of the sloths went extinct. Some of the smaller sloths did survive and migrated to the treetops. Today, there are six species left living in the rainforest canopies of Central and South America. Hanging out in the trees is a good way to avoid predators, and there are pntely of laeevs to eat. But this diet has its drawbacks. Animals extract energy from food and use that energy to move around, mtiniaan their body temperature, keep their organs working, and all the other aetvticiis necessary for survival. But leaves don't contain much energy, and that which they do have is tough to extract. Most hrreoibevs splpeunemt a leafy diet with higher energy foods like fruit and seeds. But sloths, especially three-toed sloths, rely on leaves almost exclusively. They've evolved fenily tuned strategies for coping with this restricted diet. First, they extract as much energy from their food as possible. Sloths have a multi-chambered stomach that takes up a third of their body, and depending on the species, they can spend five to seven days, or even weeks, processing a meal. The other piece of the puzzle is to use as little energy as possible. One way sloths do this is, of course, by not moving very much. They spend most of their time eating, rnsietg, or sleeping. They descend from the canopy just once a week for a bohratom break. When sloths do move, it's not very fast. It would take a sloth about five minutes to cross an average nroeiobghhod street. This unhurried approach to life means that sloths don't need very much muscle. In fact, they have about 30% less muscle mass than other animals their size. Sloths also use less energy to keep themselves warm because their body temperature can fuutltace by about five degrees Celsius, less than a cold-blooded rlepite, but more than most mammals. These physical and behavioral adaptations minimize the sloth's energy eduntxiepre, or metabolic rate. Three-toed sloths have the slowest metabolism of any mammal. The giant pnada is second slowest, and two-toed sloths come in third. Moving slowly has allowed sloths to thrive in their treetop habitat. But it's also made the sloths themselves a great habitat for other oinagrsms, iuilncndg agale, which provides a little etrxa camouflage, and maybe even a snack. Sloths may not be giant anymore, but that doesn't make them any less rmebarklae.

Open Cloze

In 1796, ______ _________ received a box of bones he couldn't identify. A long, sharp claw reminded him of a lion, but the arm bones suggested a larger animal, one about three meters long. Thinking it might be huge unknown species of _____ American lion, Jefferson warned explorers Lewis and Clark to keep an eye out for this mysterious predator. But Jefferson's box of _____ didn't come from a lion. They came from an extinct giant _____. ___________ ground sloths first ________ around 35 _______ years ago. Dozens of species lived across North, _______ and South _______, alongside other ancient creatures like mastodons and giant __________. Some ground sloths, like the ____________, were cat-sized, but many were massive. Jefferson's sloth, Megalonyx, weighed about a ton, and that was small ________ to megatherium, which could reach six metric tons, as much as an elephant. They ambled through the forests and savannas using their strong arms and sharp claws to ______ plants and climb trees, grazing on grasses, leaves, and prehistoric avocados. In fact, we might not have avocados _____ if not for the giant ______. Smaller _______ couldn't swallow the avocado's huge seed, but the sloths could, and they spread avocado _____ far and wide. Ground sloths flourished for millions of years, but around 10,000 years ago, they _______ disappearing along with the Western Hemisphere's other giant mammals. Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other _______, maybe humans, who arrived in the region around the time most of the sloths went extinct. Some of the smaller sloths did survive and migrated to the treetops. Today, there are six species left living in the rainforest canopies of Central and South America. Hanging out in the trees is a good way to avoid predators, and there are ______ of ______ to eat. But this diet has its drawbacks. Animals extract energy from food and use that energy to move around, ________ their body temperature, keep their organs working, and all the other __________ necessary for survival. But leaves don't contain much energy, and that which they do have is tough to extract. Most __________ __________ a leafy diet with higher energy foods like fruit and seeds. But sloths, especially three-toed sloths, rely on leaves almost exclusively. They've evolved ______ tuned strategies for coping with this restricted diet. First, they extract as much energy from their food as possible. Sloths have a multi-chambered stomach that takes up a third of their body, and depending on the species, they can spend five to seven days, or even weeks, processing a meal. The other piece of the puzzle is to use as little energy as possible. One way sloths do this is, of course, by not moving very much. They spend most of their time eating, _______, or sleeping. They descend from the canopy just once a week for a ________ break. When sloths do move, it's not very fast. It would take a sloth about five minutes to cross an average ____________ street. This unhurried approach to life means that sloths don't need very much muscle. In fact, they have about 30% less muscle mass than other animals their size. Sloths also use less energy to keep themselves warm because their body temperature can _________ by about five degrees Celsius, less than a cold-blooded _______, but more than most mammals. These physical and behavioral adaptations minimize the sloth's energy ___________, or metabolic rate. Three-toed sloths have the slowest metabolism of any mammal. The giant _____ is second slowest, and two-toed sloths come in third. Moving slowly has allowed sloths to thrive in their treetop habitat. But it's also made the sloths themselves a great habitat for other _________, _________ _____, which provides a little _____ camouflage, and maybe even a snack. Sloths may not be giant anymore, but that doesn't make them any less __________.

Solution

maintain
fluctuate
thomas
herbivores
armadillos
bathroom
extra
reptile
compared
america
algae
neighborhood
prehistoric
central
bones
activities
resting
uproot
remarkable
sloth
jefferson
supplement
expenditure
animals
appeared
panda
leaves
plenty
species
today
sloths
megalonychid
started
north
trees
million
organisms
finely
including

Original Text

In 1796, Thomas Jefferson received a box of bones he couldn't identify. A long, sharp claw reminded him of a lion, but the arm bones suggested a larger animal, one about three meters long. Thinking it might be huge unknown species of North American lion, Jefferson warned explorers Lewis and Clark to keep an eye out for this mysterious predator. But Jefferson's box of bones didn't come from a lion. They came from an extinct giant sloth. Prehistoric ground sloths first appeared around 35 million years ago. Dozens of species lived across North, Central and South America, alongside other ancient creatures like mastodons and giant armadillos. Some ground sloths, like the megalonychid, were cat-sized, but many were massive. Jefferson's sloth, Megalonyx, weighed about a ton, and that was small compared to megatherium, which could reach six metric tons, as much as an elephant. They ambled through the forests and savannas using their strong arms and sharp claws to uproot plants and climb trees, grazing on grasses, leaves, and prehistoric avocados. In fact, we might not have avocados today if not for the giant sloths. Smaller animals couldn't swallow the avocado's huge seed, but the sloths could, and they spread avocado trees far and wide. Ground sloths flourished for millions of years, but around 10,000 years ago, they started disappearing along with the Western Hemisphere's other giant mammals. Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other species, maybe humans, who arrived in the region around the time most of the sloths went extinct. Some of the smaller sloths did survive and migrated to the treetops. Today, there are six species left living in the rainforest canopies of Central and South America. Hanging out in the trees is a good way to avoid predators, and there are plenty of leaves to eat. But this diet has its drawbacks. Animals extract energy from food and use that energy to move around, maintain their body temperature, keep their organs working, and all the other activities necessary for survival. But leaves don't contain much energy, and that which they do have is tough to extract. Most herbivores supplement a leafy diet with higher energy foods like fruit and seeds. But sloths, especially three-toed sloths, rely on leaves almost exclusively. They've evolved finely tuned strategies for coping with this restricted diet. First, they extract as much energy from their food as possible. Sloths have a multi-chambered stomach that takes up a third of their body, and depending on the species, they can spend five to seven days, or even weeks, processing a meal. The other piece of the puzzle is to use as little energy as possible. One way sloths do this is, of course, by not moving very much. They spend most of their time eating, resting, or sleeping. They descend from the canopy just once a week for a bathroom break. When sloths do move, it's not very fast. It would take a sloth about five minutes to cross an average neighborhood street. This unhurried approach to life means that sloths don't need very much muscle. In fact, they have about 30% less muscle mass than other animals their size. Sloths also use less energy to keep themselves warm because their body temperature can fluctuate by about five degrees Celsius, less than a cold-blooded reptile, but more than most mammals. These physical and behavioral adaptations minimize the sloth's energy expenditure, or metabolic rate. Three-toed sloths have the slowest metabolism of any mammal. The giant panda is second slowest, and two-toed sloths come in third. Moving slowly has allowed sloths to thrive in their treetop habitat. But it's also made the sloths themselves a great habitat for other organisms, including algae, which provides a little extra camouflage, and maybe even a snack. Sloths may not be giant anymore, but that doesn't make them any less remarkable.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
ground sloths	3

Important Words

activities
adaptations
age
algae
allowed
ambled
america
american
ancient
animal
animals
anymore
appeared
approach
arm
armadillos
arms
arrived
average
avocado
avocados
avoid
bathroom
behavioral
body
bones
box
break
camouflage
canopies
canopy
celsius
central
clark
claw
claws
climb
compared
competition
coping
creatures
cross
days
degrees
depending
descend
diet
disappearing
dozens
drawbacks
eat
eating
elephant
energy
evolved
exclusively
expenditure
explorers
extinct
extra
extract
eye
fact
fast
finely
flourished
fluctuate
food
foods
forests
fruit
giant
good
grasses
grazing
great
ground
habitat
hanging
herbivores
higher
huge
humans
ice
identify
including
jefferson
larger
leafy
leaves
left
lewis
life
lion
lived
living
long
maintain
mammal
mammals
mass
massive
mastodons
meal
means
megalonychid
megalonyx
megatherium
metabolic
metabolism
meters
metric
migrated
million
millions
minimize
minutes
move
moving
muscle
mysterious
neighborhood
north
oncoming
organisms
organs
panda
physical
piece
plants
plenty
predator
predators
prehistoric
processing
pushed
puzzle
rainforest
rate
reach
received
region
rely
remarkable
reminded
reptile
researchers
resting
restricted
savannas
seed
seeds
sharp
size
sleeping
sloth
sloths
slowest
slowly
small
smaller
snack
south
species
spend
spread
started
stomach
strategies
street
strong
suggested
supplement
survival
survive
swallow
takes
temperature
thinking
thomas
thrive
time
today
ton
tons
tough
trees
treetop
treetops
tuned
unhurried
unknown
uproot
warm
warned
week
weeks
weighed
western
wide
working
years