Ord's Kangaroo Rat
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Ord's Kangaroo Rats
(Dipodomys ordii) are common and widespread in the United States and Mexico. In
Canada, the species occurs in the sandhill areas of southeastern
Alberta and southwestern Saskatchewan. Kangaroo Rats are included on the
Blue List of species that may be at risk in Alberta because of their
unique habitat requirements and localized occurrence in the province.
The Committee On the Status of Endangered Wildlife In Canada (COSEWIC)
currently considers Ord's Kangaroo Rat to be vulnerable.
The Ord's Kangaroo Rat occurs in grassland and open scrubland
environments with sparse vegetation and sandy soils. They tend to
prefer habitats that provide smooth, sparsely vegetated substrates with
workable soils because of their bipedal locomotion, fossorial nature,
and medium body size. Active sand dunes are important natural habitat
for Kangaroo Rats; however, eroding sand dunes are becoming rare in
Alberta and Saskatchewan because of gradual climate change and human
induced changes in the landscape. In recent years, Kangaroo Rats have been found to be abundant on roads, fireguards, and
other areas frequented by humans near the sand hills in southeastern
Alberta.
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Ord's Kangaroo Rat is a member of the family Heteromyidae, a group of
New World rodents that is recognized for inhabiting extremely arid
environments. There are 24 species of Kangaroo Rat, of which Ord's
Kangaroo Rat appears to be the most common and widespread. They are
medium sized rodents with orange-brown dorsal pelage and white ventral
fur, five toes on each foot, large eyes, and particularly long tails.
The species' large hind limbs and feet facilitate the bipedal, hopping
style of locomotion for which Kangaroo Rats are named. These Rats are
mainly granivorous and collect food items and nest material in their
external, fur-lined cheek pouches. Kangaroo Rats meet their daily energy
requirements with one maximum cheek pouch load of seeds. They are
entirely nocturnal desert animals that are highly fossorial and cache
their food underground in complex burrow systems. Accordingly, they are
adapted for water conservation and can survive without water for long
periods of time. Water conservation is achieved mainly by physiological
and behavioural abilities to reduce water loss. For example, they
produce highly concentrated urine. Similarly, Kangaroo Rats have the
most concentrated milk of the terrestrial mammals. The nasal passages of
Kangaroo Rats are convoluted to facilitate counter-current heat exchange
and promote condensation of moisture, thereby minimizing respiratory
water loss.
Ord's Kangaroo Rats do not live communally and prefer a somewhat
independent lifestyle and will aggressively defend their burrows, food
caches, and surrounding areas from intruders. During relatively bright
nighttime conditions, above ground activity is
minimal, presumably to reduce detection by visually-oriented predators.
Also, the structure of the middle ear appears to be an adaptation for
predator detection as it is most sensitive to low frequency sound.
Erratic bipedal movement should aid in predator avoidance, because this
style of locomotion favors energy efficient retreat across open ground
to the safety of burrows. Ord's
Kangaroo Rats might also foot drum and this is an important behaviour
because foot drumming alerts snakes that they have been detected, and
causes them to retreat rather than investigate.
Despite the extent to which Kangaroo Rats have evolved anti-predator
strategies, they are important prey for many raptors, reptiles, and
mammals, some of which are considered to be at risk in Alberta.
Potential predators in Alberta include Burrowing
Owls, Great Homed Owls,
Long-eared Owls, Short-eared Owls, Snowy Owls, Bull Snakes, Prairie
Rattlesnakes, Badgers, Bobcats, Coyotes and Long-tailed Weasels.