A Cat that Wasn't a Cat at All (Amplify)

The Cat who Wasn't a Cat at All

When it comes to fossils, cases of mistaken identity are not uncommon. Paleontologists might think that they have found a fossil from one species, when it actually turns out to be from different species. Often, these mistakes are corrected as paleontologists make closer and more careful observations.

Multiple Choice

What does a paleontologist study?

• A scientist that studies plants

• A scientist that studies fossils

• A scientist that studies the body

• A scientist that studies space

Open Ended

How do observations help paleontologists?

One interesting case of mistaken fossil identity happened in 1796, when workers dug up a pile of strange-looking fossilized bones. A scientist observed the fossils and noticed long limbs and big claws. Without making careful comparisons to other fossils, the scientist guessed that the bones belonged to a huge cat, much bigger than a lion. He named it Megalonyx (“giant claw”), and believed it might still exist in the western part of North America at the time.

Dropdown

The scientists believe the fossils belonged to a big cat because they found ​ .​ ​

Select answer

Match

Match the following

• Fossil

• DNA

• Archaeological dig

• Carbon dating

evidence of life from the past

genetic material

excavation site

determining age of artifacts

• evidence of life from the past

• genetic material

• excavation site

• determining age of artifacts

Years later, another scientist studied the fossils and made more careful observations. After making close comparisons with fossils from other species, this scientist determined that the animal often walked on its hind legs. Cats do not walk on their hind legs, so this discovery probably meant that the fossil was not a cat.

​

Multiple Choice

Closer observation from new scientists discovered that the animal often walked on their hind legs.

• True

• False

Draw

Draw what you think the animal from the fossils would look like if they walk on their hind legs.

​The scientist discovered that the fossils actually belonged to a giant sloth. This species had been extinct for a long time—since the last Ice Age, more than 10,000 years earlier. Even though the mistake became clear with time, the name of the giant sloth was never changed. The Megalonyx jeffersonii (which isn’t a cat at all!) is a reminder that it is important to make careful and precise observations in science.

​The scientist discovered that the fossils actually belonged to a giant sloth. This species had been extinct for a long time—since the last Ice Age, more than 10,000 years earlier. Even though the mistake became clear with time, the name of the giant sloth was never changed. The Megalonyx jeffersonii (which isn’t a cat at all!) is a reminder that it is important to make careful and precise observations in science.

Multiple Choice

Which time period did the giant sloth,Megalonyx jeffersonii, lived in?

• Cretaceous period
• Ice Age

• Triassic period
• Jurassic period

Multiple Choice

What body structure did the second scientist use to determine that the first scientist had misidentified the fossil?

• The hind foot
• The claws

• The tail bone

• The spine