The role of scent marking in a free-ranging, female black-footed cat (Felis nigripes)

1. What they did

The black-footed cat is one of the world’s smallest wild cats (1 to 2 kg), solitary, nocturnal and secretive, so little was known about their lives in the wild. Small cats mark mostly by spraying a fine mist of urine onto grass and bushes, which the authors say is almost impossible to find later by indirect methods. To learn how and why this cat scent marks, they watched one directly.

• Catching and collaring. A female was caught in her den, immobilized and fitted with a 50 g radio collar.
• Habituation. She was habituated until she ignored a four-wheel-drive vehicle following her at 10 to 15 m. Each evening she was found by radio-telemetry and followed by headlight and spotlight, for anything from half an hour to the whole night.
• Recording. Every 2 to 10 minutes or so, the observer spoke the time, her position and the number of urine-sprays since the last record into a pocket dictaphone. Her position was first plotted against surveyed markers, and early in the study by Global Positioning System (GPS) instead. Her path and every spray were mapped on a grid of 16 ha cells.
• Other marking behaviours. They also recorded defecation, squatting urination, cheek-rubbing, rolling on her back and clawing the ground.
• Linking marking to breeding. Spraying rates (sprays per hour of time she was in view) for each of seven observation periods, from May 1993 to October 1994, were compared with her reproductive state: pregnant, with dependent kittens, or neither.

2. What they found

Urine-spraying

• Urine-spraying was by far the most common form of marking, seen 1454 times in 575 hours over 402 km. She lifted and vibrated her tail while treading with her hind legs, spraying small karroid bushes, grass clumps and, rarely, termite mounds.
• The authors say this count is certainly an underestimate, because the act is brief and she was hard to watch at night.
• With dependent kittens: no spraying at all.
• Pregnant: spraying at low rates (0.84 and 0.95 sprays per hour). It began after mating and stopped before the birth.
• Before mating: in the June/July 1994 period, about one and a half months before the calculated mating for her third litter (8 to 13 August 1994), her nightly rate rose from 5.22 to 35.92 sprays per hour within 15 days. She once sprayed 40 times in 619 m and 41 times in 685 m. That one period gave 1348 of the 1454 sprays.
• In May 1993, with no kittens and not pregnant, she sprayed at a modest rate (average 2.07 sprays per hour).
• Before the mating that produced her second litter (December 1993), no spraying was seen, probably because she still had her first litter.

Where she marked

• Sprays were not concentrated along the edges of her range. The densest spraying was in the areas she used most during the rest of the year.
• Without kittens she covered a wider area each night. Kittens kept her close to the den, because she kept returning to feed them.

Other marking behaviours (all rare)

• Cheek-rubbing on grass tufts, bushes or termite mounds: 7 times, all in the June/July period.
• Squatting urination: 42 times, all in periods when she was not spraying; three times on top of a termite mound.
• Defecation: 19 times, casually while travelling, never with a scrape. Only two scats were covered, both close to the kittens’ den. She was never seen to defecate on prominent objects, but scats were found on termite mounds.
• Rolling on her back: 4 times. Clawing with the front paws: twice.
• Kittens were never seen to scent mark.

Breeding

• She raised three litters: two litters of two kittens each in the 1993/94 summer, and a third at the start of the 1994/95 summer.
• The first litter was found on 19 November 1993, already over five weeks old. Births of the second (20 February 1994, in a hollowed-out termite mound) and third (20 October 1994) litters were observed.
• She cared for kittens for about 10 to 12 weeks; they were left alone at the den while she hunted. The father played no part in their care.
• Oestrus could not be recognized from her behaviour and no matings were seen. Mating dates were back-calculated from a gestation of 63 to 68 days.
• On 6 December 1993 an adult male was seen following the female while she still had kittens, 9 to 14 days before the calculated mating for her second litter. He showed no interest in the kittens.

3. What they concluded

• The main role of urine-spraying in this female appears to be advertising her reproductive state to males. The authors suggest this matters for a solitary cat with a very short oestrus (about 36 hours) in an arid land, where she may have only one night to mate. The rise six weeks before mating may reflect one or more earlier oestrous periods.
• Spraying throughout her range, especially where she spent the most time, may help a neighbouring male find her within a shared range.
• She also sprayed at low rates whenever she had no dependent young, so spraying may also help maintain social spacing through mutual avoidance. Spraying may keep cats apart for most of the year and bring the sexes together for mating.
• Stopping spraying while she had kittens, and covering scats near the den, may reduce the risk of predators (for example, black-backed jackal) finding the kittens. The authors suggest that early in the breeding season spraying helps her breed, while later protecting the kittens she has already invested in matters more.
• Cheek-rubbing, seen only before mating, may also signal reproductive state. Scats may play a role in communication, which needs further study. Squatting urination appears to be simply elimination. The few claw scratches seemed not to be signals, since she did not reuse paths; they may be comfort behaviour or help shed old claw sheaths.
• Understanding scent marking in this species needs data from males and females, their use of home range, and how neighbouring cats respond to marks. The authors planned to address these as more cats were studied.

6. Other technologies, skills or innovations

• Habituating a small, secretive wild cat so that she could be followed closely from a vehicle at night and watched directly.
• Radio collar (50 g, range about 800 m), Yaesu FT 290 R II receiver and two 3-element Yagi antennas.
• Switching from surveyed ground markers to GPS for positions, so less time was spent fixing her location and fewer sprays were missed.
• Spoken notes on a pocket dictaphone every few minutes, mapped onto a 16 ha grid.