Spotlight on Vet Medicine
November 27, 2006
Porcupine Prenatal Care
National Zoo vets diagnose pregnancy and monitor the development of a baby porcupine during gestation and after birth.
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| Prehensile-tailed porcupines are also known as coendous. |
Native to South America, prehensile-tailed porcupines (Coendou prehensilis) live in the trees of tropical forests, where they eat leaves, flowers, shoots, and roots. Unlike the much larger common porcupine (Erethizon dorsatum) with which many North Americans are familiar, these seven-to-12-pound rodents have a prehensile (grasping) tail, which they use to tightly hold onto vines and branches in their arboreal habitat. The flexible tail is quite long, ranging from 13 to 23 inches; the animal's body length ranges from 17 to 22 inches.
Prehensile-tailed porcupines are active only at night. During the day, they can be found sleeping, in a den in a hollow tree or crouched in a branch. Their quills, which have barbed tips that easily embed and work their way into flesh, protect them from predators.
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| Babies have soft red quills. |
Reproduction can occur anytime during the year and the gestation period is about seven months. The single offspring is highly precocial. The newborn’s eyes are open, its prehensile tail works, and it is able to climb almost immediately. But for the quills, which in newborns are soft and red, a newborn looks pretty much like a miniature adult. Young are weaned at ten weeks and are mature at 19 months.
Is She or Isn’t She?
Prehensile-tailed porcupines live at the National Zoo’s Small Mammal House. In November 2005, the Small Mammal House keepers suspected one of the females, Winnie, was pregnant. She had mated earlier and was now gaining weight. The keepers asked Zoo veterinarians to confirm their diagnosis through an ultrasound exam. The Small Mammal House keepers have trained their porcupines very well, which makes doing an ultrasound possible without anesthesia or restraint—something vets can’t do with many other species.
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| Distracted by a food treat, Winnie ignores the ultrasound probe. |
Zoo veterinarians used an ultrasound machine to visualize the female’s uterus. During the exam, keepers distracted Winnie with sweet potatoes and bananas—her favorite treats. The ultrasound clearly showed her uterus was filled with fluid, typical of pregnancy. And, making it definitive, a small beating heart could be seen. Once Winnie gave birth, vets determined she had been 110 days into her pregnancy when the ultrasound was conducted.
Watch the video of the ultrasound below!
Monthly Checks
Veterinarians checked the mother-to-be monthly with ultrasound examinations to make sure she was healthy and the baby was developing normally. Using ultrasound, veterinarians could visualize and check the fetus’s spine, liver, heart, and kicking legs. Her keepers monitored Winnie’s weight and appetite.
A Baby Is Born
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| Fresco gets an exam. |
On February 8, 2006, Winnie delivered a baby boy. At 12.8 ounces (a little more than three sticks of butter), he was within the normal range of neonatal weights for the species. Mother and baby were fine. The baby, later named Fresco, climbed soon after birth and steadily gained weight during his first months of life.
Veterinarians continued to check up on him, performing a thorough examination under anesthesia when he was six months old. Now nine months old, he weighed six pounds on his last exam, is nearly adult size, and no longer lives with his mother.
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| Winnie and her infant, Fresco. Fresco is nursing in the image on the left. |
Come visit the porcupines at the Small Mammal House!
In 1985, National Zoo scientists published the first data on the life history and behavior of prehensile-tailed porcupines living in a zoo. They determined the species’ gestation length, neonate size, growth rates, and more—all of which were previously unknown. Check out their paper from the Journal of Mammalogy:
“The Biology of Prehensile-tailed Porcupines (Coendou prehensilis) in Captivity.”
