Wild Dogs in the Serengeti
by Roger Burrows
(2002)
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A 'Youth First' protocol in the African wild dog (Lycaon pictus) male social hierarchy:- Roger Burrows (October 2002)
A 'youth first' social protocol has been identified in the Serengeti African wild dog (Lycaon pictus) male social hierarchy. The protocol ensures that when either one of an alpha pair dies a male from the youngest cohort in the pack assumes the status of alpha in the resulting all male group and that all the females emigrate. This protocol which is probably unique in mammals is basic to understanding the reason for the phenomenon of sudden 'pack dissolution' and therefore has considerable general practical implications for the conservation of the species throughout Africa. What has not previously been recognised is that this 'youth first' protocol is not a consequence of pack dissolution it is the causal factor. The identification of the existence of such a protocol provides an explanation for the basic demographic characteristics of Lycaon populations including occasional male recruitment (philopatry) but frequent young male, and invariable young female, emigration from their natal packs in Serengeti. It also explains why younger males become alpha when adopted by older males and why young males cause social disruption in artificially constructed packs both in captivity and those subsequently released. The recognition of this protocol highlighting the importance of longevity of the alpha pair in a Lycaon pack, single sex immigrant groups of females, and all male groups of mixed cohorts resident on a home range, in maintaining populations is vital. It also warns that pack dissolution will follow if either of the alpha pair dies as a result of invasive research or during translocations and that alpha individuals should not be routinely immobilised for blood sampling and the fitting of radio-transmitters, as is the case in southern Africa, if conservation of this highly endangered species is to be successful.
Based on observations in Serengeti in the 1970s, it was concluded that young males were normally recruited for life into their natal pack (male philopatry) and whilst a few males emigrated young females invariably did so. This was noted as unusual behaviour for a social mammal (Frame et al. 1979, Frame & Frame 1976).
A feature of the demography in the 1970s, a period when reproductive success was very low and immigrants very rare, was that a group of males of mixed cohorts remained on their former packs home range after the death/disappearance of the females. These male groups continued to raise any pups. The males were joined within a few weeks, months, or in one case two years later, by immigrant females who adopted any pups still present. The pack was reconstituted and so continuity was maintained through the male line (Estes & Goddard 1967; Frame et al. 1979).
A young male emerged as the new alpha breeding individual in the pack, and bred with one of the new females. The assumption of alpha status by one of the youngest males took place with no evidence of overt physical aggression (Frame et al. 1979). The previous alpha male and any of his older male relatives present become subordinate but vital 'mentor' to all the other group members. The new alpha retained his status as long as his partner was present in the pack. This 'youth first' protocol in the male reproductive hierarchy has unfortunately not been widely recognised (Burrows 1995).
In the 1980s male recruitment did not occur with all young males and, as in the 1970s, all young females emigrating usually as yearlings from their natal pack in single sex groups sometimes of mixed cohorts with the females leaving before the males. When brothers of different cohorts emigrated a younger male became alpha in the pack subsequently formed. No all male groups resident on a home range were located post 1984 (Burrows 1995).
Based on data from Serengeti for two periods with contrasting reproductive success, very low in the 1970s and high in the 1980s, it can be concluded that young males were recruited into their natal packs only if pup survival was low or one parent died. Occasional recruitment of young males and secondary emigration of any older female sisters of the alpha female resulted in a sex ratio highly skewed to males in some packs in the 1970s (Frame et al. 1979). Demographic changes brought considerable social changes in the Serengeti packs (Burrows 1995).
The sudden dissolution of established packs into single sex groups has been reported in Lycaon in woodland habitats in Kruger and Moremi; and in Selous the presence of one or more former alpha males in many packs is reported (Reich 1985; McNutt 1996a; Creel & Creel 2002).
All the behaviour and the varying demography over time described above for Serengeti packs during 1970s and 1980s and pack dissolution and former 'alpha' males remaining in their packs in other populations can be explained by the existence of a 'youth first' protocol .
This protocol ensures that following the death of either of the alpha breeding pair in a pack a member of the youngest male cohort present eventually emerged as the new alpha male in the social hierarchy of the male group when new females joined the male group to re constitute the pack with the other males in the alpha's cohort being recruited (Frame et al. 1979; Burrows 1995).
The dissolution of the original pack was inevitable as there are behavioural barriers to inbreeding in free living packs. Consequently once one of the alpha pair died the females in the packs, including the alpha if she had survived, had no chance of breeding with the new related younger alpha male and she and the other females emigrated. Unlike the male, however, the former alpha female in the pack retained her status over her relatives in any new pack they helped to form.
The youth first protocol can explain observed differences in Lycaon demography in Serengeti both during periods of low reproductive success in the 1970s, when all male groups of mixed age on a home range which produced the characteristic male skewed sex bias of that period were frequently located, and during a period of high reproductive success 1985-1991 when such groups were not found (Frame et al. 1979; Burrows 1995).
It has been suggested that male philopatry, patrilineal kin groups, and female emigration described in early reports of social behaviour in Serengeti Lycaon are based merely on a limited set of data and not generally applicable to the species in other habitats (McNutt & Boggs 1996).
This conclusion appears to be incorrect as, not only can it explain pack dissolution in other habitats, but the Serengeti 'youth first protocol' has recently been found also to apply to Lycaon packs both free living in other habitats and to a variety of captive situations with, in each case, a younger male becoming alpha :-
i. in Kruger National Park
(NP) South Africa a son replaced his father as dominant breeding male in
a newly formed pack with the former alpha becoming the most subordinate male
in the Kwa-Gamakhulu Pack (Reich 1985).
ii. when free living males adopted a younger unrelated male(s) in
Moremi Game Reserve (GR) Botswana (McNutt 1996b).
iii. in wild born and captive born males in captive packs in Mkomazi
GR, Tanzania (Visee et al. 2001).
iv. in an artificially constructed mixed age group in a captive pack
in South Africa (van Heerden &Kuhn 1985).
v. in a released group of captive bred, hand reared individuals (from
Botswana) and older wild bred males, (from Kruger NP), introduced together
into Madikwe GR, South Africa (Hofmeyr 2001).
vi. when related males form different cohorts emigrated together in
Serengeti in the 1980s (Burrows unpublished data).
The same 'youth first' behaviour in such disparate groupings of free living and captive males with varying natal pack origins suggests that such behaviour is not only a characteristic of the species but has a genetic basis.
The protocol can explain not only 'pack dissolution', but also occasional male philopatry and female emigration from their natal packs not only in Serengeti but in Kruger NP, and Moremi GR and the younger male taking over the older in Kruger Reich 1985; McNutt 1996a).
However in Kruger NP although the Serengeti 'youth first' protocol applied in at least once case (see ii above) no explanation for this behaviour is made. It is claimed that in this Lycaon population the linear male hierarchy is age related and headed by older males (Reich 1985).
Unfortunately the data upon which this claim is made are unclear as in most cases the relationships and relative ages of the males in a group was either unknown or assumed. The lack of a firm data basis is also evident in the widely quoted claim that in one Kruger Pack a daughter fought her mother and mated with her father (Reich 1985). The relationships of the individuals involved cannot be determined based on the data provided by Reich.
It is essential in any Lycaon study that a photographic file of each individual in each study pack is compiled with each side of the individuals shown as they differ in markings often considerably. Fortunately such data was collected in the Serengeti study from 1967-1991 and the fate of individuals over a number of years can be determined from photographic records and in published diagrams (e.g. Frame et al 1979. Scott 1991).
It is essential to identify each individuals in each pack on a regular basis. Merely recording the number of unidentified adults and juveniles seen together either during ground observations in dense bush/woodland, where not all the pack can be seen at the same time, and certainly not individually identified, as is often the case in southern African populations, or relying on aerial tracking counts is totally inadequate. From such 'lumped' data it is impossible to recognise changes in behaviour, composition or social relationships in packs over time. It is perhaps not surprising that most of the conclusions on Lycaon behaviour from Kruger NP are based on suppositions and extrapolations which are highly questionable.
The Serengeti 'male first' protocol
can explain the reason why pack life is short in Kruger NP where, based on
data from alpha individuals selected for radio collaring, high mortality
(35% per year) occurs from either unknown, or 'natural causes' including
high lion predation (Mills 1992, Girman et al. 2001; McNutt 1996a; McNutt
& Boggs 1996). Short pack longevity, which is also characteristic of
Moremi woodland packs, would be predicted from the 'youth first' protocol
in any population with high adult particularly high alpha mortality.
The 'male first 'protocol can explain why in Kruger a younger male took over
alpha status from his father and why, in Selous GR, more than one former
alpha male occurred in many packs (Creel & Creel 2002).
As a consequence of the 'youth first' protocol male wild dogs will accept as leader of their pack or group: -
i. Their parents whilst both are
present in the pack.
ii. A same age sibling in a dispersing group.
iii. A younger brother in a dispersing group of mixed cohorts
iv. A younger brother (or son in the case of a former alpha) in an all male
group following pack dissolution.
iv. An unrelated younger male in the case of a male group adopting pups.
Females will accept as leader:-
i. Their parents whilst both are
in the pack.
ii. Their mother at pack dissolution when they emigrate from their natal
pack with her in an all female group following the death of their father.
The former alpha retains her status when with her daughters.
iii. An older sister when in a dispersing group of mixed cohorts, but not
their mother's sister.
Young males will not accept any older unknown, non related individual, as surrogate leader of their pack which is perhaps a reason why Lycaon has not been domesticated despite its close proximity to Homo spp. for at least 1 million years.
It also explains why, in captivity, social disruption including severe fighting is reported in cases where males from different cohorts and natal packs are mixed together. In five instances where older males were introduced to females with a litter of pups the male pups persistently harassed the older males to whom they were not related (Hofmeyr 2001). Such behaviour would be predicted from the 'Youth first' protocol in the male reproductive hierarchy.
The protocol explains the lack
of overt aggression between pack members so characteristic of the Serengeti
packs. However the behavioural mechanism whereby in free living packs older
males suddenly and passively accept their subordination to younger even unrelated
males is unknown. It is conceivable however that a small mutation some 2-3
MY ago in a canid ancestor of Lycaon caused a genetic 'switch ' which, in
the presence of pups, switches 'on' the behavioural imperative to adopt,
feed and later to defer to pups at kills, to be left permanently 'on' and
so also apply to the male breeding hierarchy.
Based on the basic protocols of 'Youth first' and 'Leadership', both the
formation and structure of free living packs and the often dramatic and sudden
changes in their composition but persistence over time can be explained.
The existence of these protocols also explains why, if not followed, as has
been the case in most artificially constructed packs, high levels of aggression
and mortality occur in captive packs and why those 'packs' introduced to
the wild usually disintegrate.
The 'youth first' protocol also highlights the importance of the alpha pairs in the packs making up a population in maintaining its stability. It also highlights the dangers inherent in invasive management techniques which, as in the Kruger NP and Moremi GR research, select one or both of the alpha individuals for immobilization, blood sampling and the fitting of a radio transmitter (Mills 1992; McNutt 1996a; Girman et al. 2001).
Such invasive interventions may inadvertently cause death or reduced longevity of an alpha and so lead inevitably to pack dissolution (Burrows 1992; Burrows et al 1994). The unique Lycaon 'youth first' protocol and its consequences for leadership and pack longevity has therefore considerable practical implications for the future conservation management of this highly endangered species both in the wild and in captivity.
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