Trophic Level II - The Herbivores Naked Mole Rats Page 16

  Heterocephalus galber

Length: 8-10 cm (3.1"-4")

Weight: 30-80 g (.06 -.18 lb.)

Tail: 2-5 cm (.8"-1.9")

Status: Common, but rarely seen

Habitat: Naked mole rats are found in plains, thickets, grasslands and all types of savannas including grassy glades in forests. The environment must offer subterranean storage organs (i.e. below ground portions of the plant where food can be stored) and roots. The micro-climate below the soil must be stable. Their presence in the ecosystem can be determined by the small volcano-shaped mounds their digging produces.

Food: Naked mole rats eat the roots of dominant trees such as Acacia and Commiphora trees. They also eat the roots of vines and lilies. Other food includes bulbs and tubers of various plants.

Behavior: Naked mole rats are unusual mammals. They are well named. They live in underground burrows like moles. Like true rats, their incisor teeth are well developed and are used for digging through the earth. They are virtually blind and almost hairless. Mole rats have fewer than 100 hairs on their bodies.

Unlike most mammals, naked mole rats are not warm-blooded. When these animals were exposed to temperatures between 11.6 C and 36.6 C (53 to 98 ° F) in a laboratory setting, their temperature always stayed one degree above the air temperature. At 11.6 C (53° F), they entered a stage of temporary rigor mortis. They appeared to be dead! They revived when the researchers warmed the air.

In the wild, naked mole rats would never experience such cold temperatures. Underground temperatures are fairly constant day and night. If they do get cool, the rats huddle together for warmth.

Because naked mole rats live in underground burrows, they are seldom seen by tourists. That does not mean they are uncommon. Mole rats live in colonies that can number in the hundreds.

Insect-like Mammal

Mole rat society in some ways resembles that of insects. Like termites, there is a queen mole rat that does all of the reproducing. She will have a litter of pups every 80 days. She averages 12 pups per litter and may have 4 litters a year. Most of the other members of her colony are non-breeding virgins.

The queen makes certain that they do not breed. She bullies and pushes any female that shows signs of ovulating. The queen identifies these females by scenting their urine. When a female naked mole rat is about to ovulate, her urine contains the hormone progesterone that alerts the queen to the impending event. The bullying so terrifies the subordinate female that she fails to ovulate.

Should the queen die, several females may begin to ovulate. As they do, they attack any other females in a similar condition. Fights, sometimes to the death, occur until one female emerges as the new queen.

A single male is her mate and he bullies other males and prevents them from mating as well. The pair rules the reproductive life of the colony and all of the other mole rats help feed the young and defend the colony against snakes.

Many naked mole rat colonies are made up of members that are genetically the same. Generations of mole rats may have interbred since they are often unable to cross open ground to other colonies.

Predators: Very few animals prey on these rodents thanks to their life underground.

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Dave Taylor's African Safari - Book 3: Trophic Level II - The Herbivores (Standard Version)
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