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| Ring-tailed vontsira |
Today, in order to distinguish what we used to call "Madagascan mongooses" from the real sort, we tend to use the local Malagasy word and describe them as "vontsiras".
By far the most common species, and perhaps the most frequently seen mammalian carnivore on the island, is the ring-tailed vontsira (Galidia elegans). Even so, it remains a relatively unknown animal to the outside world, and, in part due to the relative isolation of Madagascar, has not received much attention from zoologists either. The scientific studies that mention it generally do so in combination with the rest of the carnivoran community on the island, rather than spending their time looking at it specifically. Often, it makes sense to look at the larger picture before we focus on individual species, and we're still trying to do that first part.
They have a similar body shape to some of the more slender mongooses, with short limbs and a bushy tail. They are a similar size, too, being 30-36 cm (12 to 14 inches) in length, plus a tail about two-thirds that again. Their coat colour varies considerably; almost a rich chestnut red seems to be the most common, and the tail is striped. There are at least two subspecies, with one having a paler coat than the other, but whether other variations in coat colour represent distinct populations or just individual variation is less clear.
It inhabits damp tropical jungles, avoiding the drier woodlands of the south, but otherwise seems relatively flexible, which may explain its relative frequency. For example, it often leaves the cover of trees to venture into nearby cleared land and seems tolerant of human activity so long as it isn't actively threatened. Even so, the contraction of forest across much of Madagascar leaves it now largely confined to the eastern coast, although some populations do exist elsewhere. It can be found from coastal woodlands all the way up to the treeline on the mountains at around 1,950 metres (6,400 feet).
It is also a generalist feeder, mostly preying on rodents, birds, and the local insectivores, as well as invertebrates, but able to adapt its diet to whatever is available. For example, it has been observed fishing in streams, probably helped by its forefeet that are partially webbed. One report concerned a pair of vontsiras descending on a mass aggregation of mating toads, killing them in a frenzy that left more dead than they could reasonably consume. They will also eat lemurs, including some much larger than themselves, although it's possible that at least some of these are scavenged from the kills of other animals, such as eagles.
They are most active during the day, but can adjust their behaviour in the presence of competitors, such as dogs and civets that have been introduced to the island. They are mostly solitary, but are sometimes seen in small family groups of up to four, perhaps indicating more social cohesion than is typical for their relatives, the civets.
They are also quite vocal, having been recorded making a range of sounds, including whistles, growls, and screams. One particular high-pitched screech is associated with encountering another member of their own species perceived as dominant, in which case the weaker animal bends its front legs down to press its chest against the ground, raising its head and baring its teeth in a submissive posture. They also communicate through scent markings, having perineal glands similar, but less developed than, those of civets, as well as others on the cheeks and chin, much as cats do.
Although they are capable of climbing trees, they don't spend much time in them, sleeping in rocky crevices and hollows at the base of trunks, or else in burrows that they construct themselves. Their digging skills have also been put to use in extracting rodents trying to escape into their own burrows.
Mating is a noisy but brief affair, although it apparently doesn't involve neck-biting by the male as seen in many similar species. Females give birth to a single young at a time, which is born fully-furred and capable of hearing, but doesn't open its eyes until the fourth day. They are weaned at around two months, and can hunt for themselves at three, but often stay with their parents for up to a year. Rare sightings of family groups of four may indicate that, at least some of the time, females can raise two consecutive children in the same year.
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| Boky-boky |
Over on the western side of the island, we have the boky-boky (Mungotictis decemlineata), also known as the "narrow-striped vontsira" and by variations of those two names. It's similar in body form to its ring-tailed relative, but is slightly smaller at 25 to 30 cm (10 to 12 inches) in body length. The body and tail fur are grey, with ten narrow stripes of darker fur running down the back.
The boky-boky inhabits moderately dry deciduous forest dominated by baobab trees. Such woodlands are more common on this side of the island, sheltered from the monsoon winds of the Indian Ocean. It primarily eats insects and other small invertebrates, which form about 85% of the diet. Many of these are beetle grubs dug from the dead wood of fallen trees or from out of the soil surface. The remaining 15% includes various larger prey, such as rodents and small reptiles. Analyses of their droppings include some larger animals, such as lemurs, but it's likely these are the result of scavenging - which is probably also responsible for the local myth that they kill and eat large constrictor snakes.
Like the ring-tailed species, they are active during the day, although they may be more inclined to climb trees. At night, they will shelter in burrows during the dry season, but more often use tree hollows when the ground becomes too damp at other times of the year. Compared with many similar animals, they are surprisingly sociable, living in groups of up to five individuals, even ignoring any young they may have. The groups are usually single-sex (infants aside), although males may, at least temporarily, sometimes join the female groups. Individual groups are tolerant of one another, rarely resorting to fighting, although the males scent mark places where their territories overlap, and the females just seem to avoid one another.
Unlike the ring-tailed species, they make only a narrow range of sounds, the most common of which has been described as a "bouk-bouk" sound that obviously goes a long way to explaining their Malagasy name. The young are precocious, being able to open their eyes from birth, and teething for the first time at just four days old. Unusually, all the young of a particular all-female group are placed together in a creche burrow, the entrance of which is too narrow for the mother to enter; since they are able to walk almost from birth, they emerge from the creche whenever the mother calls them to feed, and are otherwise well hidden.
The alternative name "narrow-striped vontsira" implies the existence of a broad-striped species and, in fact, there are two. The one that actually carries that name, the broad-striped vontsira (Galidictis fasciata) inhabits much the same area of humid, east-coast forest as the ring-tailed species. However, it is more picky about its habitat and avoids direct competition by being entirely nocturnal, only active when its potential rival is asleep.
It is similar in size to the narrow-striped species, but has a greyish-biege coat marked with broad black stripes running the length of the body. Other than this, very little is known of it, and it's apparently unfamiliar even to many of the locals. Doubtless, a combination of shy habits and it being a nocturnal animal living only in dense woodland contributes to its elusive nature. When it is seen, it's often in pairs, suggesting some sort of family unit, and in other respects, it is assumed to be similar to other vontsiras, if only due to a lack of information to the contrary.
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| Broad-striped vontsira |
(You may note, incidentally, that the scientific name as given in the original paper linked above does not quite match the current one. Although the first name to be given usually stands as is, regardless of what else may happen, in this case the Latin grammar proved to be incorrect... and there's only so much the relevant registering body will put up with).
Unusually, it is not a forest-dweller, being known only from the very driest part of Madgascar, a short stretch of land near the southwest coast. The vegetation here is dominated by scrubby succulent plants vaguely resembling cactuses, which are most abundant along a fault line running through the area where underground aquifers reach close to the surface. It's not known whether Grandidier's vontsira needs to drink water, or whether it gets enough from its food... but that food, which consists mainly of cockroaches and locusts, is itself most common along the fault line. Larger invertebrates, such as scorpions, are also eaten, as are a few vertebrates, although the latter are so much larger than anything else it eats that they may well provide the majority of its caloric intake.
Grandidier's mongoose is nocturnal, sheltering in crevices of the cliff face near the fault line, and presumably in similar places elsewhere. It does not appear to excavate its own burrows, but when so much of the local rock is limestone, it hardly needs to, since natural tunnels of the right size can extend for metres into the rock, helping it shelter from the desert sun. Although they are often seen in pairs, larger groups are much rarer, although this may have as much to do with the lack of widespread resources to feed off as anything else.
One thing we do know is that, since the area it lives in may be as small as 1,500 km² (580 square miles) and its suitable habitat within that area is declining, it undoubtedly qualifies as an endangered species, and it has been recognised as such almost since it was discovered. Nor is it alone, since the boky-boky, while not so concentrated in a single area, lives in forests that are being lost more rapidly than those on the east coast, and has been formally listed as an endangered species since 2015.
The least-known species is the brown-tailed vontsira (Salanoia concolor) which has a relatively drab grizzled brown colour making it look especially mongoose-like. It lives in the humid forests of the northeast, which would make it overlap with both the ring-tailed and broad-striped species. It is active during the day, and mainly eats insect grubs that it picks from tree bark; it is assumed that patterns of behaviour, or fine details of the diet allow it to co-exist with its relatives, but the exact details so far remain elusive. It appears to be reasonably sociable as, on the rare occasions when it is seen at all, it is often in groups of two or three, but that is pretty much the extent of our knowledge.
In 2010, a population living near Lake Alaotra, much further inland than the others, was suggested to form a distinct species on the basis of geographical isolation and some differences in the body form, such as larger teeth. The area is marshy, which would also indicate a different habitat from the main species. Named as Durrell's vontsira (Salanoia durrelli) this has not been widely recognised, partly due to the lack of records, but, assuming it is valid, the population must be very small, and it would probably count as another endangered species.
Together, these form the majority of the native carnivoran species of Madgascar. However, as noted in my previous post, the reason it took so long to recognise the Madagascan carnivorans as all belonging to same family is that the remaining species look rather different, and have never been assumed to be mongooses. Next time, I will be looking at some of them.
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