Merriam's kangaroo rat
Dipodomys merriami
— Where the name comes from
Dipodomys is “two-footed mouse”, from dípous and mŷs: watching it move, one would swear it had no front legs. The epithet recalls Clinton Hart Merriam, founder of the American biological survey and inventor of the life zone concept, who first tried to map animals by belts of altitude and climate.
— Facts
- Group
- Mammals · Mammalia
- Order
- Rodents
- Habitat
- Sandy and gravelly deserts, creosote scrub
- Range
- The south-western United States and north-western Mexico
- Size
- 9–12 cm of body, tail 14–17 cm, 33–55 g
- Diet
- Seeds, shoots, the occasional insect
- Lifespan
- 5 years
— Characteristics
- 01
It drinks no water in its whole life: it obtains it by metabolising dry seeds.
- 02
Its kidneys concentrate urine five times more than ours.
- 03
It drums its feet in rhythmic sequences to communicate with neighbours underground.
— What sets it apart
It hears the snake coming before the snake moves. Its tympanic bullae take up a third of the skull and are tuned to the very low sounds made by a rattlesnake sliding and by an owl’s wingbeat; in high-speed film the kangaroo rat is seen dodging a rattlesnake’s strike with a sideways leap begun before the fangs are halfway there. The measured reaction time is a few tens of milliseconds, at the limit of what a nervous system that size can do.
