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Rock hyrax newborn and mother
The Chicago Zoological Society (CZS), which manages Brookfield Zoo, is proud to announce the birth of three rock hyraxes, one born on February 19 and two on March 24. The birth of the older baby marks the third generation of rock hyrax on exhibit—the baby, the baby’s mom, and the baby’s grandmother. Staff has not yet identified the babies’ genders or named the babies, who can be seen daily in the zoo’s Fragile Kingdom exhibit.

The 6 to 8 ounce newborn rock hyraxes are very precocious, having the appearance of miniature adults at birth and moving about their rocky environment, although very close to their mothers, within days. At 3 to 4 days of age, the newborns are already nibbling food, and by 14 days old they are eating a lot of solid food. Weaning occurs at 3 to 5 months of age and when fully grown, rock hyraxes are typically 17 to 21 inches long and weigh between 9 and 12 pounds. 

Although these small, stocky animals are shaped like large guinea pigs, they share characteristics with elephants with whom they share a common distant ancestor. Hyraxes have similar foot and leg structures and long upper incisors that resemble the tusks of an elephant. The incisors are curved, triangular in cross section, and continually growing. In addition, like elephants’ teeth, rock hyraxes flat, grinding teeth are well suited for eating grasses. They eat a wide variety of plants, including some that are poisonous to most other animals. Interestingly, rock hyraxes have a gestation period of between 201 to 245 days, about 7.5 months. Normally, mammals as small as a hyrax have a much shorter gestation period. The long gestation is likely due to the relation they have with their much larger distant ancestors.

Rock hyraxes can be found throughout East Africa in both dry savannah-like and dense forest environments. As the name implies, rock hyrax reside in rocky terrain, seeking refuge in rocky outcrops or cliffs. Hyraxes have a relatively low metabolic rate and a rather poor ability to regulate their internal body temperature. As a result, they depend on their dens, the sun, and one another to keep warm. They may live in small or large groups. Their dens have small entrances and can be located in rock crevices, cliff caves, or even within the underground dens of aardvarks. They seldom dig their own dens but may scrape out loose earth from a preexisting hole. Hyraxes’ feet and nails are not very efficient for digging. Their uniquely padded feet with specialized sweat glands give hyraxes exceptional traction when climbing steep rocky cliffs.

Although rock hyraxes are not endangered, they do need to be wary of their many predators including leopards, eagles, snakes, jackals, caracals, mongoose, hunting dogs, and spotted hyena. To avoid predation while feeding, hyraxes feed in groups with their heads facing outward from the group, allowing them to notice approaching predators. One individual, usually the most dominant male, perches nearby on a rock or a branch and guards the group. If he sees or senses danger, he gives a warning cry. Hyraxes communicate with at least 20 different vocalizations with various howls, squeaks, and grunts being typical.