Absent meerkats

The monthly reports have raised questions as to when an individual is considered last seen. On this page you find:

  • The explanations of the various abbreviations used when a meerkat is no longer in its group.
  • An example, following the complex events around the loss of the Hoax group.
  • Notes on the disappearing of groups.

Research protocol background

The research protocol generally uses the following terms to describe the events of a meerkat disappearing from the population, or group:

  • DEAD: Individuals are only marked as DEAD if they are known or very likely to be dead – e.g. their body was found, or in the unlikely event that they were observed to be taken away by predators.
  • LSEEN: Individuals are considered last seen (LSEEN) if it is unlikely that they will be observed in the KMP’s population again. A female is considered LSEEN if she is not observed in the population within one month after she left her group. A male is considered LSEEN if he is not observed in the population within two months after he left the group; in times when the number of females in oestrus is very low (e.g. during a drought), males can also be LSEEN after one month.
  • EM (EMIGRATE): An individual is considered emigrated (EM) if he/she left the group and was not accepted back within one month, but was observed somewhere else in the population after one month (female) or two months (male) had passed. In this case, he or she will be declared EM from the previous group, and immigrated (IM) in an unknown group (UNK).
  • In all of these cases, the individual is retrospectively put as EM or LSEEN in the Life History database on the exact date he or she was physically last observed; in the monthly reports, the individual is marked as EM or LSEEN after the observation span of one or two months, respectively, ended. The DEAD term is of course always noted the day the body is found.
  • DISAPPEAR: The terms APPEAR and DISAPPEAR are, for research purposes, exclusively used when an absent animal (e.g. evicted female) tries to return to his/her own group (APPEAR), but is not allowed to stay with the group (DISAPPEAR). On this website, the term “disappear” is sometimes used in a broader sense, i.e. a meerkat that is no longer observed in the monitored population.
  • LEFT/RETURN: The term LEFT are, for research purposes, only used when an individual leaves his/her own group. If the individual returns within one month (female) or two months (male), he/she is marked as RETURN in the group. If the absence is longer, the animal will be LSEEN or EM (see above.)

It happened on several occasions in the past that individuals returned to the monitored population after having been LSEEN; the longest absence noted was more than 10 months. However, an individual must be clearly identified in order that a LSEEN entry is reversed. This usually involves reading his/her ID chip implant with a reader device. The individual must be repeatedly approachable, due to the fact that the readers are taken to the field only if an identification is to be done. Single sightings are usually not enough to identify an unknown individual.

An animal that reappears after being LSEEN is marked as IMM, either in the group he/she immigrates in (usually newly founded groups), or in an unknown (UNK) group.

Example: The Hoax members

However, the disappearing of individuals and groups can sometimes be more complex, as in the case of the Hoax, Vivian or Young Ones groups. Please find below a detailled explanation of the events in the Hoax group, as an example to illustrate the protocol.

VHXF004
VHXF004 was the dominant female of Hoax, and therefore represented and defined the group: A number of meerkats is only considered a group in the Life history protocol when there is a dominant female. A group can therefore usually be considered LSEEN when there is no longer a dominant female; remaining males and non-dominant females are considered EM at this date.
VHXF004 was physically last observed on 31st October 2007. However, the group was visited up until the 7th when VHXF004 was not actually observed in the group but no other individual appeared to be acting dominant in her place (which would happen if she had gone missing). VHXF004 had become increasingly nervous since the absence from the group of some of the males and it was thought that she had become too nervous to come to the surface in the presence of observers.  So it was assumed until 7th November that she was present, but not observed. But the group were last considered being a cohesive group on 7th November. LH conclusion: VHXF004 is LSEEN in the LH database on 31-Oct-07, and LSEEN in the November LH report.

VWF076
VWF076 was observed as an individual throughout November and until December, as she wore the Hoax’ radio collar; it was not clear whether she had been evicted and was to return to Hoax or if she had joined a new group. She was put as LSEEN on 19th December, when the researchers had to remove her radio collar, since she had moved a considerable distance North towards Botswana, where monitoring is no longer possible. She was pregnant at that time, but her fate and that of her pregnancy could no longer be followed. After this event, the Life History database was updated in retrospect: she was marked as EM from the HOAX as per 7th November (when the Hoax group was considered LSEEN in the database), and part of no known group (UNK) thereafter. She could not be put into the November monthly report as LSEEN, because the researchers were still following her in December. LH conclusion: Her LSEEN dates both in the Life History database and the monthly report are thus in December.

VWM109
VWM109 left the Hoax on 30th September 2007, and was not seen thereafter; he did not return to the monitored population within 2 months. LH conclusion: By the end of November, he was therefore marked as LSEEN as per 30th September in the Life History database in retrospect, as well as LSEEN in the November monthly report.

VHXM001
VHXM001 left the Hoax on 31st October, and was seen roving at Aztecs and Moomins, before he turned up in the new Polaris group within his allocated two months. He is therefore not last seen because he has been seen alive in the population. LH conclusions: Instead, VHXM001 is marked as EM from Hoax, and IM into Polaris.

VHXM002
VHXM002’s was last observed as a member in the Hoax on 15th October. His LEFT entry was changed to an EM entry after his roving at Moomins (contrary to VHXM003, he never immigrated into Moomins), as it was clear that he had dispersed from Hoax.  He was physically observed for the last time on 20th October, roving at Moomins. As a male he had two months to either return to his group or be observed again in the population before he is marked as LSEEN. He did not appear again. LH conclusion: He was therefore considered LSEEN in the December 07 Monthly report. In the Life history database, his LSEEN date is backdated to the real event, i.e. 20-Oct-07.

VHXM003
VHXM003 left Hoax on 15th October, not to return to them. Due to the fact that he immigrated into Moomins, his LEFT entry on 15th October at Hoax was corrected to EM, in retrospect. He immigrated into Moomins on 17th October and assumed dominance, but was last observed there on 19th October, together with the other Moomins males and the younger females; yet he did not join the Moomins splinter group that left the monitored area. LH conclusion: He, like all males had two months to turn up in the population and so his emigration and last seen date was entered two months later in the Life History database. For technical reasons, he is entered as LSEEN in the January monthly report only (should be December report).

Lost groups

There is no set protocol for last seeing groups – it is at the discretion of the field management after consulting with Tim Clutton-Brock.

With Hoax, the researchers were hoping to re-find VHXF004 and the group – the problem being that a subordinate, VWF076, had the radio collar so there was always the possibility of her being evicted from the group (with Hoax, the researchers had no choice but to put the collar on VWF076 because VHXF004 was so difficult to habituate). VWF076  was followed throughout December in the hope that she might return to the group or lead the researchers to VHXF004. This is why the researchers only decided to LSEEN Hoax at the end of December, after VWF076 had moved a considerable distance from the former Hoax territory. In the Life history database, Hoax are thus retrospectively put as LSEEN on 7th November 2007, and with the November monthly report already written, they should no longer appear in the December monthy report.
The flexibility when it comes to declare a group LSEEN can be seen when comparing Vivian and Young Ones. Observation of the Vivian group was actively stopped, after their dominant female VVF029 disappeared, and no other female was acting dominant, while most males had dispersed. The date the group was considered LSEEN in the Life History database thus coincides with the day the radio collar was removed, and the remaining individuals were declared last seen.
The Young Ones group, however, are not yet considered lost, but missing: The two females both wore a radio collar, but neither them nor the poorly habituated, recently immigrated wild males could be tracked after 12th November 2007. Radio-tracking still continues throughout January. As there is no set protocol for last seeing groups, Young Ones will be declared last seen when the field management and Tim Clutton-Brock decide that it is not likely that they will be found and all tracking possibilities are exhausted.  So if they are not located again, the group will retrospectively be marked as last seen on the date that they were physically last observed, i.e. as per 12th November.
The Young Ones males VM129 and VYM130 that left when the wild males immigrated have been marked as EM in Young Ones (and are currently followed under the name of ‘Chuckle Brothers’, but are not considered a group since they lack a dominant female). The former dominant male of Young Ones, VVM037, was found dead after the group disappeared.

 

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