Big Eared Climbing Rat

Big-Eared Climbing Rat

Ototylomys phyllotis is found from the Yucatan Peninsula of southeastern Mexico to central Costa Rica. Ototylomys is found in tropical forests, both dry and wet, with abundant rocks or rocky ledges. 

Big-eared Climbing Rat

Head and body length is 95 – 190 mm and tail length usually falls between 100 – 190 mm. The body is bicolored, with a gray/brown coloration dorsally and a white/gray coloration ventrally. Hands and feet are pale. The tail is long, predominantly hairless, covered in large scales, and can be anywhere from a dark, dull gray/brown to black, with a paler coloration on the ventral surface. The eyes and ears are large and the ears are hairless. Adults and juveniles show two distinct pelage patterns.


There appears to be no specific time for breeding in Ototylomys. Average gestation period is 52 days, although caged specimens have shown periods of up to 174 days, due presumably to delayed implantation. The average of 52 days is the longest known gestation period in myomorphous rodents. This long gestation allows for highly precocial young, and foraging of young has been observed 11 days after their birth. Sexual maturity may be reached as early as 30 days after birth. Litter size ranges from 1 to 4.


The species is nocturnal and arboreal. Activity is primarily on low creepers and branches, although specimens have been observed foraging on the ground and among rocks. It is believed that individuals maintain a home range that also contains vertical components. Ototylomys is not a social species and most social interaction occurs during mating.

Food Habits

Ototylomys forages both on the ground and in trees. As it is found primarily in tropical areas, a wide variety of food sources are exploitable, with fruits and leaves being favored. In captivity they should be offered a complete diet of rodent lab blocks, and rat or mouse mix, with bits of fruit or veggies regularly. Cheerios or wheat bread are great treats, in small quantities. Do NOT feed chocolate, fried foods, salted foods, candy or junk food! They may enjoy crickets and mealworms if they are captive bred, never feed wild insects as they may carry parasites.

Vitamins, like Nutri-Cal are a good addition to their diet, and added calcium during nursing and growth due to demands on their systems at those times, but take care not to overdo it. Water bottles should be used to proved constant, clean water. Ceramic or stoneware food dishes work well for keeping seeds or fresh foods off the floor, and a wire mesh hopper that allows them to eat the lab blocks through without extra waste.

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