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Episode 32: The Inconceivable Naked Mole Rat

Naked Mole Rats are so strange and unique that they defy belief. These tiny creatures survive and thrive in the harsh desert regions of Africa. Scientists are just now unlocking their many mysteries. Their physical abilities and strange social structures teach us just how incredible nature can be. These little mammals can be found in East Africa, and specifically Ethiopia, Kenya and Somalia.

Naked Mole Rats Origins

Naked Mole Rats scientific name is Heterocephalus glaber. While closely related to the ‘blesmols,’ also known as mole rats with hair, the Naked Mole Rats are in their own genus. These specialized rodents split off from typical ‘murine’ rodents like mice and rats over 20 million years ago. It is believed today ‘s Naked Mole Rats evolved around 2million years ago.

Naked Mole Rat Physiology

The Naked Mole Rat is indeed almost completely naked, with the exception of approximately 100 fine hairs. Their skin is often pink, grey, or yellow with many wrinkly folds. They have extremely poor vision, but can see changes in light, with two small eyes. They have two large upper and two large lower teeth, often used for burrowing. Naked Mole Rats also have poor hearing with no external ears but can hear a range of low-frequency vibrations.

There are some incredible physical adaptations of Naked Mole Rats. Since these are ground dwelling mammals in large colonies they exist in an atmosphere of lower oxygen and higher carbon dioxide.

First, Naked Mole Rats live extremely long lives for rodents, with reports of up to 32 years. Average lifespans of rats and other mice are often 1-2 years.

Naked Mole Rats do not develop cancer. Due to a unique cellular mechanism, the Naked Mole Rats cells can prevent the development of cancerous masses or tumors.

Naked Mole Rats can survive up to 18 minutes without oxygen.  Due to the low level of oxygen in their burrows they have adapted to this “to us” harsh environment. The underlying mechanism is instead of using glucose to fuel their cells (bodies) they use fructose as their main sugar source, which does not need oxygen to be used.

Naked Mole Rats do not feel pain to certain stimuli like acid. With low levels of oxygen and high levels of carbon dioxide body tissues become acidic. It is comparable with human exercise and the pain associated with high levels of lactic acid in muscles.

Naked Mole Rats are “cold-blooded” meaning they do not regulate their body temperature like other mammals. Instead, they maintain their burrows around 32 C (90 F) and will huddle together to stay warm.

Naked Mole Rat Behavior

These animals are the only ‘eusocial’ mammal on Earth. This is a social organization found in insects such as the honeybee or ant colonies. These social structures are defined as having three main characteristics:

  • One single queen or egg layer, with other females tagged as workers
  • Overlapping of generations with queen and offspring
  • Cooperative brood care, or care of the young

Naked Mole Rat queens have up to three males selected to service her to produce offspring. Workers can be male or female and often are clearing, caring for the young, burrowing or acting as soldiers.

These small mammals primarily eat tubers growing in their burrows. They tend to eat the tuber from the inside out, allowing the tuber to keep growing.

Naked Mole Rat Conservation

These animals are classified as “least concern’ with stable populations and often viewed as a pest.

Organizations to Support

IUCN Small Mammals Specialist Group

Tsavo Conservation Group

Image

Cover image from Smithsonian under CC 2.0

May 22, 2018

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