44 | New Scientist | 15 January 2022
already found fossils that fill the gap, but we
don’t yet know it. “As long as we keep museum
collections properly maintained, they are
clues. It’s like a fingerprint from a cold case
that maybe should have been analysed,” says
Ashley Poust at the San Diego Natural History
Museum in California. Indeed, he and his
colleagues have recently reanalysed one
specimen that appears to push back the origins
of nimravids in North America. “It was just
mislabelled in the collection here,” he says.
Nevertheless, the consensus is that the
Cat Gap is real, that new discoveries may shrink
it but they won’t close it altogether. “Now
that we have an understanding of the Cat
Gap, we can go back and look at the collections
to see just how big it really is,” says Poust.
The bigger question is how did nimravids
go from prowling far and wide across North
America to dying out. One theory is that
volcanic activity played a role. Nimravid fossils
have been found in abundance just east of the
Rocky mountains, where the land under their
paws was undergoing major changes during the“ The ‘Cat Gap’
that followed
the nimravids’
demise lasted
6.5 million
years”
ALLA^GILL/SHUTT
ER
ST
OCKAlthough North America is no longer
inhabited by cat-like nimravids (see main
story), it is home to the world’s third
largest cat species. Jaguars (Panthera
onca) are thought to have arrived here
from Eurasia via the Bering land bridge
less than 1 million years ago, long after
nimravids became extinct. Once found
across the southern US, they eventually
settled in the mountains of Arizona and
New Mexico. But in the 20th century,
they were driven close to extinction, with
the US government paying hunters to
kill predators known to target livestock.
Killing jaguars is now illegal in the US,
but today there is just one lone specimen
in the country: a male filmed in the
Santa Rita mountains, Arizona, in 2016.
Now, conservationists say the time is
right to bring these cats, which can still
be found in Mexico and regions further
south, back from the brink in the US.
A study published in 2021 found that
an area of about 80,000 square
kilometres across Arizona and New
Mexico has enough water and prey to
support a population of between 90
and 150 jaguars for at least 100 years.
“What we know about jaguars is
they’re supremely equipped to survive
in a multitude of ecosystems, which is
not unusual with top-level predators,”
says Michael Robinson at the Center for
Biological Diversity in Tucson, Arizona.
Making space for them to thrive on
their native lands in the US would let
them once again play their role in the
ecosystem there, which could set off
a domino effect. “Stalking predators,
such as the felids, lead to evolutionarily
induced behaviours in prey animals.
They’re part of what keeps the deer
and elk incredibly alert,” he says.
Large cats can still pose a threat
to livestock, but the region’s economy
is based less on cattle ranching than
it once was. The study suggests that
with careful management of fences
and water sources, local people could
live peacefully with jaguars. Better yet,
big cats could drive ecotourism in the
area, just as reintroduced wolves have
done in Yellowstone National Park.Bring back
the jaguars!
La Garita Caldera in
Colorado once caused
problems for nimravids