Category: Ferans

Nandinia (African palm civet)

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Nandinia binotata. Image credit: Mathias D’haen, under CC BY-NC 4.0.

Named by: Gray, 1843

Taxonomy: Synapsida, Sphenacomorpha, Sphenacodontia, Sphenacodontoidea, Therapsida, Theriodontia, Cynodontia, Probainognathia, Mammaliamorpha, Mammaliaformes, Mammalia, Theria, Eutheria, Placentalia, Laurasiatheria, Ferae, Carnivoramorpha, Carnivora, Feliformia, Nandiniidae

Included species: N. binotata

Viverrids (civets) are one of those groups of organisms that have experienced dramatic taxonomic revision in recent times. Particularly with the advent of molecular phylogenetics, many groups formerly considered viverrids have been booted out. These ex-civets include mongooses (more closely related to hyenas than to civets), Malagasy carnivorans such as the fossa (Cryptoprocta ferox) (also more closely related to hyenas), and linsangs (more closely related to cats).

One former viverrid, however, sits alone in the family tree of feliforms, the large clade of carnivorans that comprises all species more closely related to cats than to dogs, encompassing all of the groups mentioned in the previous paragraph. The single living species in the genus Nandinia is descended from a lineage that may have split from all other feliforms 40-50 million years ago and has no close living relatives. Despite this, it is still known by the vernacular names “African palm civet” and “two-spotted palm civet”.

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Phylogenetic tree of feliform relationships.

Nandinia may be phylogenetically lonely, but in many parts of their range they are considered the most abundant small carnivorans in the forests of central Africa. They are generally solitary, though this doesn’t mean that their lives are devoid of social interaction. The home range of a dominant male overlaps with those of several females and smaller males, and he communicates with the females in his range using a loud cry that can be heard up to almost 1 km (3280 ft) away. The smaller males, on the other hand, generally keep to their individual sectors within the larger range of the dominant male, a sensible choice given that conflicts between males are known to be fatal. Several individual Nandinia may gather in close proximity where food is abundant, such as groves of fruiting trees.

Fruit constitutes roughly 80% of the diet in Nandinia, and they assist in the seed dispersal of at least 12 different plant species. After feeding on fruit for 5-10 minutes at a time, Nandinia typically rest for about 2 hours on a tree branch a short distance away before returning to partake in another meal. Perhaps not coincidentally, the digestive system of Nandinia works quickly; it takes only 2-3 hours for consumed fruit to pass through the digestive tract. When more than one individual is feeding in the same tree, females have priority access to food.

Their largely frugivorous habits should not be taken as a indicator of Nandinia lacking predatory prowess, however, considering that they are known to go after small primates such as pottos (Perodicticus potto) and juvenile monkeys. Nandinia dispatch their prey by holding it down with their forefeet while biting them all over the body. Their climbing skills serve them well when hunting; they have been observed catching fruit bats and raiding the nests of weaver birds at the tips of very thin branches.

The arboreal agility of Nandinia is facilitated by their large, ridged foot pads and a long, balancing tail. They are able to climb smooth posts, hang upside down by their feet, and descend trees headfirst. They can also jump across gaps 1 m (3.3 ft) wide and leap 1.8 m (5.9 ft) vertically into the air. One anecdotal account described an individual Nandinia repeatedly climbing to a height before apparently parachuting to the ground by extending its legs and tail. As one might expect, regular performance of such stunts can be risky. A wild specimen was once caught with healed fractures across its femur and kneecap.

Despite their acrobatics, it appears that Nandinia rarely venture higher than 40 m (131.2 ft) above the ground, preferring heights of 5-35 m (16.4-114.8 ft). During the day they rest on thick horizontal branches or in tree hollows 12-15 m (39.4-49.2 ft) above ground. Unlike many other specialized arboreal mammals though, Nandinia display no aversion to traveling and foraging on the ground, and are regularly caught in traps set at ground level.

References

—Albertonykus

Phataginus

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Phataginus tricuspis. Image credit: Николай Усик, under CC BY-SA 3.0.

Named by: Rafinesque, 1821

Taxonomy: Synapsida, Sphenacomorpha, Sphenacodontia, Sphenacodontoidea, Therapsida, Theriodontia, Cynodontia, Probainognathia, Mammaliamorpha, Mammaliaformes, Mammalia, Theria, Eutheria, Placentalia, Laurasiatheria, Ferae, Pholidotamorpha, Pholidota, Manidae

Included species: P. tricuspis (type), P. tetradactyla

Pangolins are some of the most peculiar mammals. They are toothless, relying on their long, sticky tongue to capture insect prey. They are also covered in a coat of hard scales that serve as protection from predators. These unusual features may recall similarities with the anteaters and armadillos of South America. However, genetic studies have shown that the closest living relatives of pangolins are the carnivorans, the great radiation of predatory placental mammals including cats, dogs, bears, seals, and more.

Living pangolins are currently split into three different genera, of which the smallest are members of the genus Phataginus. Weighing around 2 kg (4.4 lb) as adults, Phataginus live in the forests of central Africa. Like other pangolins, they can roll into an armored ball to protect themselves from attack, but their scales are generally thinner and flimsier than those of larger pangolins. This, combined with their small size, likely makes them more vulnerable to predation, and they may rely more on their repulsive anal secretions to deter large carnivores.

P. tricuspis is the better-studied of the two species of Phataginus. Members of this species can retract their eyes into their sockets (an ability apparently shared by at least some other pangolin species). They regularly forage in trees and are able to climb quickly using a “caterpillar-like” motion. To get down from trees, they spiral around the tree trunk while supporting themselves using their tail. They have also been observed performing more expeditious descents by rolling into a ball before dropping directly to the ground.

Despite being at home in the trees, however, P. tricuspis spend much of their time on the ground, perhaps due to the greater availability of their preferred prey on the forest floor. While feeding, they flick their scales continuously to shake off attacking soldier ants and termites, and sweep their tail from side to side to herd their prey within reach. After feeding, they groom themselves meticulously using their hind feet to uncover any insects that may have ventured underneath their scales. During the day, P. tricuspis rest in tree cavities or in shallow burrows. They breed throughout the year; one field study rarely found females that were not pregnant.

Pangolins are typically solitary, but P. tricuspis exhibit behaviors suggestive of greater sociality in this species. Pairs have been found using the same tree hollows, and in captivity groups of up to six individuals have been observed sharing sleeping quarters and following one another around in single file. Juveniles in particular appear eager to seek contact with other pangolins and even their human handlers. One individual regularly returned to visit its handlers over a period of six months after being released into the wild. In general, P. tricuspis seem like a friendly bunch. However, males are known to fight to the death by slashing each other with their front claws. P. tricuspis have poor eyesight, so their social contacts are established using scent. They are also quite sensitive to vibrations, including sound.

Though most pangolins are competent climbers, members of the other species of Phataginus, P. tetradactyla, are particularly specialized for arboreal life. Their incredibly long, prehensile tail contains up to 47 vertebrae, more than that of any other mammal. The tail is strong enough to support their entire body weight for long periods, allowing them to hang by their tail. P. tetradactyla almost never descend to the ground. They rest in tree hollows or hollowed-out insect nests. Cavity-nesting birds are reportedly known to mob them, perhaps seeing them as competition for tree hollows.

P. tetradactyla are said to be more diurnal than P. tricuspis, which may reduce competition between the two species. It is likely that the highly arboreal habits of P. tetradactyla, along with their preference for forests that experience regular flooding, correspond to a specialization in feeding on ants and termites that avoid floods by nesting high in the forest canopy. Such insects tend to have well-developed chemical weaponry, so it is plausible that P. tetradactyla possesses adaptive countermeasures to these defenses. However, due to the lack of detailed study, such specializations, if present, remain unknown.

Reference

  • Kingdon, J. and M. Hoffmann (eds.). 2013. Mammals of Africa Volume V: Carnivores, Pangolins, Equids and Rhinoceroses. A&C Black Publishers Ltd., London. 560 pp.

—Albertonykus