Palaeolagus, meaning ancient hare, is an extinct genus of lagomorph
in the family Leporidae. While closely related to modern rabbits,
its’ shorter hind legs indicate it ran more like rodents,
to which it is more distantly related, than hopped like rabbits
of today. Palaeolagus also chewed differently than rodents due to
having two pairs of incisors in the upper jaw as opposed to a single
pair in rodents. With jaws adapted for nibbling grass and plant
material, Lagomorphs chew sideways, while rodent jaws work back
The earliest leporids described from the fossil record of North
America and Asia date to the upper Eocene some 40 million years
ago. Selective pressure ostensibly drove them to become ever faster
and better at running and jumping. Other fossil finds from Asia
indicate more primitive progenitors of Palaeolagus existed in the
lower Eocene; this pushes the like date of divergence of rabbit-like
and rodent-like lagomorphs back to more than 50 million years ago.
Perhaps the biggest adaptive advantage of lagomorphs is in the procreation
department, a fact often used as a humorous metaphore by Homo sapiens.
Palaeolagus was surely highly prevalent in the savanna environment
of Oligocene North America, the size and fragility of their fossils
make them rare.
This Oligocene matrix from the badlands of Wyoming contains two
Palaeolagus that are largely intact, an even more rare occurrence.
Perhaps this pair were lovers in life. The beautiful preparation
has left them in matrix, perhaps as they expired together, snuggled
for eternity in their rock grave.