Scent Marking in the Binturong, Arctictis binturong

1. What they did

The binturong is a little-known, tree-dwelling member of the civet family (viverrids) from the dense forests of northeastern India, Indochina, Indonesia, Thailand, Burma and Malaysia, with shaggy black fur, ear tufts and a long, partly prehensile tail. A pair had lived at the National Zoological Park in Washington, D.C., since 1965 without breeding. In 1972 the zoo tried to bring the female into heat by injecting her with a hormone, Pregnant Mare’s Serum Gonadotropin (PMSG), on five days in July.

Around this treatment, from May to August 1972, the author and a helper watched the pair for over 48 hours, mostly in the early morning and late afternoon when the animals were most active. They recorded how often and for how long each behaviour occurred in 30-minute blocks. The watches were grouped into four stages: before treatment (I), the first part of the treatment (II), the later part when activity dropped (III), and after treatment (IV).

The paper describes how binturongs leave scent, and what affected the rate and form of marking.

2. What they found

How binturongs mark

• Perineal gland marking. Binturongs have a large oval scent gland between the tail and the genitals. Some scent is probably left whenever they sit or climb, but they also marked four particular raised posts on purpose: three vertical metal poles and one sloping limb.
• On the sloping limb, the animal hung upside down in a sloth-like position, scuffed its feet, and pulled its gland along the limb (an upside-down perineal drag). On the vertical poles, it pulled itself up the wire mesh and pressed its gland against the pole while pulling its body upward.
• This marking was seen 13 times in the male and only 3 times in the female, but the posts were clearly important. When the pair was moved to their outdoor enclosure after the winter, both sniffed and then marked these same posts straight away.
• Metatarsus scuffing. The animal takes its weight on its front legs and shuffles its hind feet alternately, rubbing the naked heel on the ground with the toes raised. This happened alone or together with urinating or gland marking.
• Urine. Binturongs urinated in a squat with the tail on the ground, which soaked the tail. They scuffed before, during and after urinating, so their heels became covered in urine, which they then carried to other places when scuffing. The author suggests the wet tail probably also spreads urine onto limbs when climbing.
• Dung. Binturongs defecated at particular spots (locus-specific defecation).
• Other rubbing. Both animals pressed the side of the body against the wire mesh at one site, and the male rubbed his forehead and cheeks at another, for up to 25 seconds. Both animals regularly sniffed these two spots.

Differences between the male and the female

• The male scuffed more often than the female in every context, and with more scuffs per bout (10.8 against 6.0 on average).
• Both scuffed more when urinating or gland marking than when scuffing alone. The male averaged 15.5 scuffs per bout when urinating, 14.4 when gland marking and 5.3 when scuffing alone; the female 7.6, 10.3 and 3.6.
• Short scuffing bouts were more common than long ones.

What triggered marking

• Scuffing was common when the animals were disturbed, for example when the female was caught for her injections and when the pair was first moved outdoors.
• When perfume was put on two of the male’s favourite marking spots at the end of the study, he soon gland-marked there.
• After the female’s first injections, both animals marked more and sniffed urine and scent marks more. The male spent 40.1 seconds per 30 minutes sniffing urine and marks in Stage II, against 12.2 before treatment, and his anogenital grooming rose from 16.0 to 48.5 seconds, often with an erection.
• Of the female’s 3 gland marks, 2 were in Stage II, and 16 of her 24 scuffing bouts were in Stage II, although it was only 12 of the 48 hours.
• About six days after treatment began, activity dropped sharply, and marking and sniffing dropped with it.
• The pair seldom interacted, but just after treatment they sniffed and groomed each other more. On the day after treatment the male lay facing the female for about 3 minutes while she fed, trying now and then to approach, which had not been seen before. He also came down from his platform to sniff her urine during and after she urinated.

3. What they concluded

• Binturong scent marking is highly specialized. Gland marking in both an upright and an upside-down posture had not been reported for any other viverrid; only the fossa genus (Cryptoprocta) uses an upright posture, and for a chest gland instead. The upside-down posture is presumably derived from the upright one.
• Two kinds of stimulus affect marking: conflict or disturbance (an earlier author saw scuffing when binturongs were excited, impatient or waiting for food), and odours, both familiar and strange.
• The male’s increased marking, sniffing, genital grooming and erections after the female’s treatment suggest he was responding to changes in her odour, her behaviour, or both.
• The marking posts likely kept the previous summer’s odours, as genet and civet gland secretions keep their smell on wood for 4 years.

6. Other technologies, skills or innovations

• An “Owleye” night vision device for the night watches.
• Timed behaviour watches in 30-minute blocks, recording the frequency and duration of each behaviour.