Patterns of Scent Marking with Urine and Faeces Amongst Carnivore Communities

1. What they did

In 1954 Konrad Lorenz suggested that a singing nightingale and a dog lifting its leg were doing the same job. Birdsong had since been shown to defend territories, but what about scent marks? In this chapter from a Zoological Society of London symposium volume, David Macdonald reviews what was then known about how carnivores (dogs, cats, hyenas, weasels, civets, bears and their relatives) use their urine and faeces to leave messages. He asks whether the places where marks are left reveal what the marks are for.

He draws on:

• His own work on red foxes. He hand-reared foxes from eight weeks of age and walked them daily through an area about the size of a small wild fox territory, so that he could watch their marking in detail. He combined this with night observations of wild foxes and simple field experiments, such as placing urine from strange foxes near the edge of a vixen’s marking range, or digging up a favourite marking site and moving it 10 m a day across the countryside.
• Field studies by others. Many relied on reading tracks and signs: for example, wolf researchers found packs’ tracks from aircraft and then followed 240 km of trails in the snow, counting urine marks, scrapes and faeces.
• Unpublished data and personal communications from many colleagues, on species from jackals and hyenas to feral cats and mink.

He compares urine marking and faecal marking between species, and within species living in different habitats, and looks for ecological reasons behind the differences.

2. What they found

Urine marks

• Red foxes. From about five months old, vixens switch from a few long urinations a day to many small “token” marks, aimed at visually conspicuous objects, often with a leg lift. One vixen left over 100 token marks on each one-hour walk in midwinter, and some sites were re-marked on more than 70 days.
• Foxes marked more on paths than off them (10.4 tokens per site and 0.71 sites per metre on paths, against 6.37 and 0.25 off paths), and more often on each site where conspicuous sites were scarce. Marks along a path matched how often that path was travelled.
• Captive vixens marked only within a clearly defined area and often turned back at its edge. Marking fell sharply near the edge (0.95 sites per metre 100 to 235 m from the edge, 0.17 within the last 70 m). A vixen turned back when she smelled urine from a strange fox placed near her border, but not when she met her own transplanted urine. Inside her range she overmarked strange urine. The author concludes that territorial defence is a probable, but not proven, function.
• Wolves. Only high-ranking adults made raised leg urinations. Along the trails in snow researchers found 583 of them, on average one every 450 m, almost all on visually conspicuous objects, with 40% at trail junctions. Nose prints in the snow showed marks were later sniffed. Marks were twice as frequent near territory edges as in the centre (2.67 against 1.27 per km), giving a “doughnut” of scent with “olfactory hotspots”. Lone wolves hardly marked at all (one series of marks in 72.2 km of tracking), yet still investigated marks and trail junctions. Lone foxes and foxes visiting neighbouring territories also stopped token marking, and silver-backed jackals did not mark on long trips to water.
• Fresh versus old marks. Wolves overmarked marks a few days old but not those about a month old. Foxes walked the same path twice within an hour marked only 30% as much the second time.
• Seasons and pairing. Marking peaks in winter for wolves and foxes, often at the time of pair formation. Newly formed pairs of wolves, foxes, jackals, hunting dogs and others “double mark”, overmarking each other’s urine; in wolves this fades as the pair bond ages and is absent in pairs that later fail to mate.
• After fights. High rates of urination follow encounters in wolves, jackals, spotted hyenas, red foxes, lions, domestic dogs and cats.
• Other species. Bobcats, lynx and tigers urine mark throughout their territories; pumas scrape vegetation into piles and urinate on them; a lioness treads her urine into mud and so soaks her paws; some civets and the binturong soak their feet or tail. Bears roll in urine and rub on marking trees: in coastal British Columbia, 17 of 18 marked trees were amabilis fir, all near active bear trails, and a fishing line stretched across the scars showed trees were used more often than tracks had suggested.
• Foraging. One study found red foxes urine mark spots where food has already been eaten, so the smell says “no food here”, a kind of “book keeping”. Foxes in the author’s study did not mark sites holding caches, but often marked emptied cache sites, large prey before eating it, and dug-out rodent burrows.

Faeces

• How many in one place. Red foxes left 80% of their faeces singly, almost always on or near conspicuous objects such as molehills; 5 to 10 faeces may lie along 50 m of well-used fox trail. Cacomistles, striped hyenas and golden jackals more often used middens (groups of faeces). Many species use middens, including spotted hyenas, maned wolves, pine martens, dwarf mongooses, raccoon dogs and dholes.
• Where in the territory. Red foxes scattered faeces all over their territories; coastal otters made middens near their holts; golden jackals left middens “like a string of beads” around their territory border, with single faeces on shrubs inside; badgers had both border middens and some near their setts. Feeding badgers coloured bait and recovering the markers from middens showed that the middens marked territory borders. Badger latrines were near landmarks such as car tracks, vegetation edges and fences more often than expected.
• Hyenas and civets. Spotted hyena long-term middens were on trails, 61% at trail junctions; tracking showed hyenas passed middens about three times for every two times they marked them, and moving faeces showed it was the site, not the faeces, that triggered fresh marking. African civet middens (civetries) were mostly along roads and trails and in clearings rather than dense bush.

Same species, different habitats

• Spotted hyenas hunting resident prey lived in large clans with border middens; those following migratory prey formed small groups and left small middens along trails.
• Striped hyenas left faeces apparently at random in the Serengeti, but made small middens near stable feeding sites in Israel.
• Golden jackals with scattered food left single faeces; where food was clumped and super-abundant they lived in large groups with border middens.
• Inland otters had middens on range boundaries; coastal otters had them at holts.
• Dominant feral cats left faeces on conspicuous sites along trails in good rabbit habitat, while subordinates buried theirs; house cats bury their faeces.

Many scents in one place

Middens and marking sites gather many odours: scrapes, anal gland pasting, and gland secretions from the feet, face and tail region. At spotted hyena latrines, 43% of active visits involved both defaecating and scraping. Up to 70% of red fox faeces may be on sites already marked with urine. Different species (wolves and foxes, striped hyenas and jackals) may also mark at each other’s sites.

A cost of marking

Prey may detect marks: deer keep to the edges of wolf territories, aardwolves may use middens to hide faeces from the termites they eat, and woodmice reacted more strongly to weasel faeces than to other odours.

3. What they concluded

• Much evidence links urine and faecal marking to holding a territory, but too much weight has been placed on this one role. Marks found only inside territories, or seen during aggression, do not prove that they defend territories or signal aggression. Scent can serve many functions at once.
• Only a few species (European badgers, spotted hyenas and golden jackals) have been found to ring their borders with middens. All live in large groups defending fairly small, stable territories at high density. For wide-ranging wolves, hunting dogs and lions, keeping middens along such long borders would probably be too much work.
• Other middens are tied to trails and junctions or to dens. Dens are a valuable resource and a centre of activity, so they are good places to leave information.
• How food is spread across a habitat, and how that shapes a species’ social life, may explain where scent is left. Stable food patches may be heavily marked, clumped food can concentrate marks, and short-lived food may make marking pointless.
• Scent marking should be expected to vary within a species, between populations and between individuals, just as other parts of social life do. Field experiments, and ways to measure an animal’s internal state before and after smelling a mark (for example by biotelemetry), are needed.

4. How tracking was or was not used

Many of the reviewed studies relied on tracks and signs. Wolf researchers located packs’ tracks from the air, then followed 240 km of trails in the snow, identifying raised leg urinations, squat urinations, faeces and scratching from signs in the snow, and spotting nose prints where marks had been sniffed. Lone wolves were followed for 72.2 km and 158 km of tracking, recording which trail junctions they investigated. Spotted hyena middens were studied partly through tracking, which showed how often hyenas passed middens without marking. Bear marking trees were found near bear trails, and a fishing line showed they were visited more often than the tracks alone suggested. The author’s own fox work was mainly direct observation of tame and wild foxes.

5. Tracker or observer certification

Not reported. The review does not say who did the tracking in the studies it describes.

6. Other technologies, skills or innovations

• Hand-reared, tame foxes walked through their range so that every mark could be watched.
• Moving a marking site 10 m a day to map the exact edge of a vixen’s marking range, sometimes to the nearest 10 m.
• Placing strange and own urine near borders to test turning back.
• Colour-marked bait recovered from middens to link middens to particular badger and jackal groups.
• Radio-tracking to define badger territories and follow a Malay civet.
• Aircraft to find wolf tracks in snow.
• A stretched fishing line across bear rubbing scars to count visits.