Water Deer Reproduction - Male Aggression

In the white hush of the reedbed, where snow lies thin and wind-stitched between the stems, illuminated by a cold December moon, two diminutive warriors face-off, their thickly furred bodies taut with purpose. Frost powders their coats and softens the earth beneath their hooves, yet nothing dulls the bright severity of their tusks, which curve downward like pale, living blades; formidable instruments whose purpose admits of no ambiguity. Breath ghosts the air as they walk stiffly side-by-side, heads held high, mouths manducating, their ears, rent and uneven at their margins, bearing silent testimony to former contests. The reeds murmur and bow around them, as though bearing witness, while the brilliant winter moonlight lends the moment a quiet, ritual gravity. The clash comes suddenly: a swift rush, a sideways lunge, the dry hiss of disturbed snow, an uncanny metallic clicking cry. Tusks meet rump, and a brief eruption of buff fur lifts and settles again, marking the passage of force. The blow drives the challenger toward the thin promise of safety among the reeds. Left alone, the victor scrapes the earth, claiming it with hoof and dung, inscribing a blunt warning for all rivals who might dare to cross this ground. In the aftermath, silence returns, broken only by the faint rasp of breath and the soft settling of snow, as the reedbed absorbs the encounter and keeps its ancient, wintry counsel.

A pair of majestic red stags or fallow bucks, antlers locked, engaged in a muscle-rippling bout of virility, is perhaps the quintessential image of the deer rut. Despite their more diminutive stature, however, the rut of the water deer is potentially no less energetic or dangerous, although as with all deer species combat appears to be a last resort and water deer have evolved a suite of highly stereotyped behaviours intended to prevent the need for violence that we'll look at in this section. Data are lacking on buck status and fight probability, in other words whether most fights are between territory holding males or between one holding a territory and one trying to obtain a territory, but neighbouring territory holders would seem to have little to gain from fighting one another. Thus, it seems reasonable that, unless a neighbour's territory is more profitable or attractive to females than yours, territory holders are more likely to be challenged by non-territory holding bucks. Indeed, in December 2025, I watched one mature buck scent mark and graze within a metre or so of another mature buck that was resting, presumably at the territory boundary, with no signs of aggression from either animal. Similarly, on countless occasions I have seen two bucks parallel walk (see below) and scent mark along what appeared to be a shared boundary, before separating and patrolling elsewhere on their side, neither showing any inclination to attack or chase the other.

In their 2008 chapter on water deer in Mammals of the British Isles: Handbook, 4^th Edition, Arnold Cooke and Lynne Farrell explained how bucks approach one another with a stiff-legged gait, heads held low (i.e., necks below horizontal, in an aspect Fritz Walther called 'Kopf-tief-Halten' or 'Kopf-tief-Drohen'; basically "head down threats") and rotated in such a way as to cause "ear-slapping". In their 2009 book Wild Deer in Britain, Roy Harris and Ken Duff note that territorial chases are sometimes preceded by the territory holder approaching the intruder with neck stretched out down to the ground and head rotating, causing "his ears to flap rather absurdly, but presumably at the same time the tusks are displayed to their best advantage". So, the ear-slapping, which can be sufficiently vigorous to be audible at reasonably close range, may not be an activity in its own right, but perhaps collateral in an attempt to show off the tusks. That said, I have observed tuskless deer perform this behaviour, including females towards over-amorous males. Regardless, during the approach, the hackles, a roughly egg-shaped patch of fur on the shoulders, may be raised, and this has been described both by Stadler at Whipsnade and Sharon Scott in Buckinghamshire.

At Whipsnade, Stadler observed that in most cases an aggressive approach never escalated, with the approach of one animal leading to the withdrawal of the other 73% of of the time. In Norfolk, I have observed a smaller buck ear-slap and mouth towards a slightly larger one that appeared to be dominant (based on scent marking and chases observed earlier) but which made no obvious response, before moving away; the dominant buck followed and gave a brief chase of the subordinate, which fled.

If the bucks get close, they will often engage in a slow, stiff walk in parallel some 10-20 metres (33-66 ft.) apart, with tails held out horizontally. Kenneth Whitehead in 1950, Centre d'Écologie générale de Brunoy naturalist Francois Feer in 1982, and most recently Gérard Dubost in 2011, all remarked that parallel walking is part of the territorial defence behaviour of bucks and it is something I have observed many times, both in captivity and the wild. Dubost and his colleagues described this as a stiff-legged walk, and there is certainly a rituality to it. Whitehead noted that ground-scraping with a foreleg and urination may accompany this parallel walk, which corresponds with my experience. Additionally, I have observed that the bucks may not always walk strictly in parallel, and may periodically separate such that one may walk a metre or more ahead of the other while retaining their parallel track. Feer suggested that this walking behaviour is the only prelude to chasing and/or fighting, and that there doesn't appear to be any specific canine display as is seen in musk deer, although German naturalists Detlev Müller-Using and Robert Schloeth seem to hint at a 'canine threat' in their chapter on deer behaviour in Handbuch der Zoologie, published in 1963. Stefan Stadler never observed such a threat in his study group at Whipsnade, and I have never seen it nor come across any other descriptions in the literature. It is possible that the mouthing behaviour that is often observed during parallel walking (see below) may draw attention to the tusks, but this remains unproven. Sometimes a walk intensifies further into a 'parallel run' that may continue for up to 100 metres, and Stadler observed:

"When, for at least one of the contestants, the distance to the centre of his territory became too large, he turned round and moved back, and this change of direction was usually matched by the opponent."

In my experience, parallel walking is often accompanied by "mouthing" -- a rapid opening and closing of the mouth/chewing action. This may be the same as the "tongue flicking in vacuum" that Dubost and his colleagues mentioned briefly in their 2011 Acta Theriologica paper, and possibly at least part of the 'self-licking' Stadler noted in his thesis, which involved the tongue appearing alternatingly on either side of the mouth at an interval of 0.5 to one second and sometimes involved 'exaggerated chewing movements'. Stadler suggested that while the origin of the behaviour may lie in aggression, self-licking may also be a self-reassuring behaviour associated with a highly excited state. Indeed, I have observed this mouthing following a chase (i.e., once a dominant buck has evicted a rival) and while bucks are patrolling, and, in December 2025, Sharon Scott described seeing a male mouthing while approaching a resting female, generating frothy saliva and making what she described as "a low-frequency guttural rumbling or bubbling noise". (I have never seen frothy saliva being produced during mouthing, nor heard any kind of vocalisation.) At Whipsnade, Stadler noted that parallel walks normally lasted only a few seconds, but in some cases went on for several minutes, and I've seen males continue for 30 metres or more, even through quite dense vegetation where either is obscured from the other. Long and intense walks in Stadler's population were often interspersed with feeding bouts (i.e., walk, feed, walk, feed), which might form the same function as the "agonistic grazing" seen in herbivores such as wildebeest.

Defaecation/urination and ground-pawing -- scraping the ground with one foot, sometimes both forefeet in alternating fashion, to disturb the vegetation and provide a visual marker to accompany application of urine, faeces, and/or preorbital secretion (see Scent Marking) -- by both individuals during parallel walking contests was observed by Stadler and is something I have also found to be common practice. Indeed, one December afternoon in Norfolk, I watched two bucks parallel walk across the back of a field and, at one point, the closest buck did a U-turn to spend 22 seconds scent marking an area of grass before catching up with the second buck to pick up where he left off. Freie Universität Berlin behaviourist Wolf-Peter Scherpe mentioned a "Drohstampfen", or 'threatening stomp' of the forefeet carried out by a buck towards another and while I know of no other similar reports, I wonder whether this might've been a misinterpretation of ground-pawing. In their 1983 booklet on water deer, Arnold Cooke and Lynne Farrell note that confrontation displays may also include a buck stretching out his neck and shaking his head from side to side. The authors describe having occasionally "been threatened by bucks in this manner".

A pursuing buck may emit a call variously referred to in the literature as a "whicker", "chirrup", "click', or "chitter" (see Vocalisation) during a chase or fight and/or immediately upon victory (see 'snow fight' video below), while retreating animals almost never appear to vocalise. Aggressors may also attempt to "scissor kick" the fleeing animal, flicking both front legs out ahead simultaneously mid-stride, aiming sharp hoof at rump. Spoored bucks typically manage to evade their pursuer either in cover or by having moved sufficiently far from the dominant animal's territory and chases tend to be relatively short, although I have seen determined bucks pursue others for several hundred metres at considerable speed. Indeed, at Whipsnade during December 2024 I watched a territorial buck break from grazing and give hard chase to another buck that passed approximately 80 metres (260 ft.) in front of it. Based on Google Maps, this chase covered about 620 m (2,034 ft. or 0.4 of a mile) before the pursuing buck broke off and began walking back. Similarly, Raymond Chaplin has observed that strangers accidentally straying into a territory are chased only as far as the boundary by the master buck, while those having challenged for the territory may be chased several hundred yards out of the territory before the pursuit ends and the territory holder returns. In the wild in Norfolk, I watched one buck approach and chase another about 320 m (1,050 ft.) before I lost them over a rise. At Whipsnade in 2023, I watched what can only be described as a 'relay chase' - one buck chased another across a field into another buck's territory, prompting this second buck to pick up the chase and pursue the interloper out of sight, while the initial buck returned to his territory. This is not always the case, though, and I have more often seen a territory holding buck watch a neighbour chase a subordinate across their patch without apparent concern. There also appears to be times when a neighbouring territory holder may intervene to the spoored buck's benefit. During December 2025, for example, Sharon Scott captured trailcam footage of one buck (buck A) pursuing a second (buck B) out of a field and across a ditch into another field, at which point the territory holder in this area (buck C) erupted from the edge of a copse and chased buck A back over to his own territory, allowing buck B to make good his escape.

If neither buck backs down, or a pursued animal finds courage, things can escalate. In some cases, bucks will face one another weaving and bobbing their heads while making "pouncing" movements to either side. Alternatively, this may take the form of more of a "bow" of the front quarters that can be accompanied by both combatants scraping the ground with their forefeet and touching noses. As with the initial approach and parallel walk, rivals may separate after this without violent contact, or a fight may ensue. Where fights do break out, they invariably appear to be the result of a challenge for territory.

We don't get to see fights very often and photographic/video evidence is rare. Most skirmishes seem to be very brief, less than one minute, and take place either in dense vegetation and/or under the cover of darkness. Indeed, perhaps as a testament to the infrequency with which we see them, in an article to Shooting Times & Country Magazine in January 2008, Ian Valentine wrote:

"They don't seem to use [the teeth] to fight with, but rather as a front. In the rut there tends to be a lot of power walking and chasing, but no fighting as such."

Fights may be relatively rare, but when they do occur they're highly energetic, almost balletic, and several authors have referred to them as "dances". The tusks are also very much involved and, as early as 1945, the 12^th Duke of Bedford noted:

"They do not fight a great deal among themselves, and when they do fall out it is not always easy to discern the cause; but such disputes as they have are fairly vicious. The rivals dodge round each other, dashing in repeatedly to attempt a cut on the top of the shoulder, and when one of them runs away the victor pursues him for some distance as hard as he can go, trying to give him something to remember him by in hooking him on the top of the rump!"

The following year, former Zoological Society of London veterinary officer James Aitchison described, quite evocatively, bucks:

"... raising their heads and striking downwards at their opponents with both tusks, viper-fashion"

Canines seem to be used in both a slashing and stabbing capacity, inflicting scratches, slices, and deep puncture wounds. Such a combat style may be hazardous to both participants, even if only one is an aggressor (e.g., one buck strikes at the rear of a fleeing rival), because contact with an opponent runs the risk of tusk damage or other injury as the target moves; and there is much movement. Stadler wrote of bucks in close neck-to-neck and/or head-to-head contact, akin to the halskampf or "neck fight" that Rosl Kirschofer, former Head of Education at the Frankfurt Zoo, described in the similarly-tusked mouse deer (Tragulidae) in 1961, the bucks jumping to and fro in front of one another with neck and head held at 30 to 60 cm (1-2 ft.) above the ground, each whickering/chittering and striking out with one or both front legs. Likewise, Lutz Heck, in his synopsis of water deer in Grzimek's Animal Life Encyclopedia, published in 1972, quoted Kirschofer's observations of the small group kept at the zoo:

"Thus our two males [father and son] continuously chased each other uttering strange trilling and drumming sounds. At the beginning of the fight, they stand opposite each other, head to head. Each animal tries to put his head over the other's neck. Then they use their teeth. This neck fighting ends by tearing out pieces of the coat and skin. Out males used to show white, hairless scars for a long time after these encounters."

The aim of the to-ing and fro-ing seemed, therefore, to be to get in a suitable position to deliver a canine blow and, during one intense fight between two ear-tagged males shortly after 11:00 one mid-January morning in 1989, Stadler described how the bucks engaged in:

"... a vicious dance for about 45 seconds (the longest fight seen up to that date). During the dance, both males deliver an uncountable number (> 20) of canine-blows aimed at the rump, back, flanks and neck of the opponent."

The victorious male was then described as appearing "dizzy", standing motionless for six minutes, and having sustained a 6 cm (2 in.) open wound on left carpal joint and "a rather tattered coat". Stadler's observations and those of others point to males attempting to kick or bite/slash the other on the neck, shoulder or rump. As each tries to protect his side and bite the other at the same time, the bucks circle. I should perhaps also note, at this juncture, that I have described approach, parallel walk, to-and-fro, chase, and fight are described as individual activities, because they're discretely distinguishable. It's important to recognise, however, that they don't necessarily follow in a complete sequence and can often be interspersed together. Two territory holders may periodically parallel walk along their adjoining boundaries without a ritualised approach first, for example. Similarly, it is not uncommon to observe a chase that is punctuated by a brief bout of circling or toing-and-froing (with or without whickering), before the chase resumes.

The only fight photographed in the northern reedbed at Woodwalton Fen was captured by Gary Dean just after 15:00 on 19^th Dec 2009. It lasted for only 12 seconds and during that time one deer "danced gracefully, but menacingly" around the other. In February 2013, Mike McKenzie photographed two bucks fighting at Claxton in Norfolk, during which they circled one another. A very brief clash caught by Sharon Scott on her trailcam during early December 2022 showed one buck leaping over the other, swinging its rear out of the way of the master buck's tusks. One late afternoon in December 2025, I watched a non-serious fight (i.e., one that resulted in no obvious injury) between two mature bucks in Norfolk. The sequence involved one buck fighting with two different males sequentially. The initial fight, which included only a couple of seconds of circling and whickering/chirruping, drove the buck into a neighbouring buck's territory from which he was chased, resulting in further conflict with the first buck. This second bout lasted for about 10 seconds and included multiple circles, both clockwise and anticlockwise, during which the territory-holding buck kicked out both his front feet simultaneously on two occasions, although neither made contact with his opponent. Each buck mouthed at the other while circling, but at no point did tusk meet flesh. The interloper was chased off, after which the territory holder urine-marked and patrolled his territory mouthing.

The photos taken by both Dean and McKenzie show the deer circling one another anticlockwise, and this is something apparent in the handful of fights and videos of skirmishes I have seen. At Woodwalton Fen, Arnold Cooke noticed that damage to ears tended to be on the left side, rather than the right, implying a propensity for bucks to circle/dance in an anticlockwise direction. Cooke observed that 20% of the 211 sightings of bucks across three winters on the reserve had damage to one or both ears, while only 1% of 305 does/yearlings had similar damage over the same time frame. This suggested that ear damage resulted from fights, rather than being inflicted incidentally, by thorns or barbed wire for example. Based on 22 years' worth of sightings, Cooke found 126 instances of ear damage, 78 (62%) of which was to the left ear, 41 (33%) to the right, and 7 (5%) to both ears; a statistically significant trend towards left ear damage. In a short article to the journal Deer in 2013, Cooke speculated, based on his data and the two photos provided by Stadler in his thesis, that left side damage might be more likely if bucks moved to their right during conflict, each exposing their left side (and ear) to their opponent - i.e., they move anticlockwise.

One final note regarding the combative behaviour of males is an unusual description from Sharon Scott. Sharon spent a couple of hours watching males rutting during a very cold spell in early January 2021, the air temperature around freezing. Several females were lying down, and a male was encircling them, chasing off interlopers. Along with the circling and lunging, she described a "chest clashing" behaviour during which each buck "put their heads back and charge at each other, butting their chests together like walruses do". Sharon has never seen them do this before and neither Arnold Cooke or I have observed it, nor come across descriptions in the literature. Sharon also described to me how she watched two larger bucks "beat up" a smaller one during December 2022, after which the defeated animal, lying in long grass, was approached and vocalised to by a female in a manner that appeared to her to be comforting.

While fights may not always result in injury -- Raymond Chaplin, for example, noted how in the five challenges he watched at Whipsnade where a fight occurred, neither buck made physical contact with the other -- it's common for males to have tufts of fur missing on (sometimes raked from) their backs and nicks in their ears, which appear indicative of at least minor contact during fights with other bucks. Tufts of fur are frequently found on the ground during the winter in areas with established water deer populations, again presumably dislodged during skirmishes. In some cases, large areas of a square metre or greater are covered in fur, suggesting an intense battle. Eye damage, broken tusks (often one, but occasionally both), rump injuries and a pronounced limp are also relatively common among males, and I have observed what appeared to be a shredded nose in one buck that was presumably caused during combat. Chaplin reported catching three bucks at Whipsnade that an eye punctured and two with "the skin of the chin torn and hanging loose". Bucks are sometimes also seen with fragments of tusk embedded in them. In January 2025, Gary Rugless photographed a buck in Norfolk with what appeared to be a piece of tusk in its right preobital gland, narrowly having avoided its eye. Likewise, in his 2020 book From Wasps to Water Deer, Martin Guy described having shot a buck with a piece of tusk embedded in his haunch and, a week later, shot one with that piece of tusk missing.

Slashes from the tusks can be deep, and while those inflicted to the rump of a fleeing buck may not be life-threatening, they can prove an avenue of infection and/or result in disability. Arnold Cooke and Lynne Farrell found a dead buck at Woodwalton Fen that had a small puncture mark on the left side of its head and a partially-healed scar some 19 cm (7.5 in.) long stretching along its neck. More recently, in March 2021, Paul Childerley observed a buck sustain a large gash on its haunch, measuring approximately six centimetres (2.4 in.) in length and about two centimetres (0.8 in.) deep, caused by a slash from the tusk of a pursing male. Whipsnade veterinary reports from the 1970s and 1980s contain several reports of water deer dying from injuries sustained during fights and during Stadler's Ph.D. studies at the zoo, 56 animals were found with some sort of injury, 44 (79%) of which were males. Of the injured males, 40 (91%) had injuries that could be attributed to intrasexual fighting and included, Stadler writes:

"... smashed eyes, ripped ears, long scars (5-30 centimetres [2-12 inches]) on virtually all parts of the body, or limping legs. In one case, a male was evidently killed during such a fight."

The latter case to which Stadler refers was an adult male found dead in one of the grass fields on 3^rd December 1987, having died the previous night. A post mortem revealed two puncture wounds in the buck's heart; the shape of each hole and their separation corresponded with the water deer canine profile and distance, suggesting it had been stabbed through the heart by the tusks of another buck. Intriguingly, in recent years Claxton Estate manager John Heathcote has found a number of animals, mostly males but also a few females, found dead with multiple slashes and puncture wounds to the head or neck. Skinning of the carcasses revealed dual puncture marks separated by the intercanine distance of a water deer buck. During the very cold and protracted winter of 2022/23, 13 dead animals were found on the estate making John wonder whether this was the work of the same "rogue buck". I'm not aware of any reports of rogue males in this species, although Paul Childerley has told me they preferentially cull old bucks with chipped tusks as they tend to be very aggressive. I would be interested to hear from anyone with experience of bucks attacking does, or being hyper-aggressive.

I'm aware of two descriptions of vanquished bucks having been caught by their pursuer - neither attempted to fight back. Feer described how one subordinate laid down in a submissive position, neck and head completely flattened to the ground; the dominant buck only attempted to bite if the subordinate raised his head. Feer commented that 'the fully prone stance had a bite-inhibiting effect'. Bob Lawrence, writing in the Shooting Times and Country Magazine during March 1982, described how:

"The chases usually end with the loser evading his pursuer in cover but in one extreme case I witnessed the victor standing over the vanquished which was lying exhausted on his back with all four feet in the air, squealing like a pig."

The observation of the pinned buck lying on its back seems to align with John Heathcote's observations of slashes to the underside of several of the animals found on the Claxton Estate. Interestingly, his 1973 book Beasts in My Belfry, the late Gerard Durrell also described a buck screaming persistently when caught in a way that 'made pig slaughter sound like music'. One of his colleagues remarked on this being the way a water deer accepts its fate.

It is typically the males that are aggressive during the rut and the female seems to play no part in the maintenance of a territory/stand, although females may exhibit agonistic behaviour outside of the rut and this, and other social interactions of both sexes, is described in Behaviour and Social Structure. Curiously, while this buck-on-buck aggression seems at its peak during December and January, when the species ruts, aggressive chases and fights may continue well beyond this, with frequent reports from deer managers and wildlife watchers during March and even April. I've watched one buck chitter at and then chase another in late April, and another pair kicking, lunging and whickering/chittering at one another through a fence on a warm early May afternoon on a nature reserve in Bedfordshire during 2025.