A technique used to measure the large African predators

A technique used to measure the large African predators

By Prof H.O. de Waal

The lion has made a huge and lasting impression on mankind.  Images of massive, maned male lions and prides of lionesses with cubs are brought to mind by mere mention of the word “lion”. One only needs to look at the wide array of statues and heraldic uses of the lion emblem on national flags. The lion (Panthera leo) is not only the largest predator in Africa, but also the most social of all 36 cat species across the globe. Although the lion is renowned for being a charismatic species, it should be noted that it is not the only large predator in Africa, and thus also has to be granted the special attention that it deserves, along with its fellow predators.

Large predators are at the top of the food chain and are easily affected by events that have an impact  on their habitat and food supply.  The activities of humans have been one of the main causes of Africa’s unspoilt natural beauty – which includes plants and animals alike. Large predators are especially affected by the increasing demand of a growing human population which has inevitably led to the fragmentation of their natural habitat and food supply. This situation is worsened by the unavoidable conflict between humans and wild animals, especially where livestock and humans are often the victims of predators. This situation has taken a deadly toll on large African predators.

As stated previously, the large African predators may be regarded as good indicators of the wellbeing of the natural environment, specifically the habitat and prey species. However, when information is gathered on the predators it should specifically also include physical characteristics of the predators and not simply reflect on their presence and numbers in an area. An important activity of ALPRU (African Large Predator Research Unit), based at the University of the Free State in Bloemfontein, is to gather biological information on the large African predators.
 
When more information is available on their habitat and prey species as well as comprehensive data on their body size, it may point to the effects that changes in habitat and thus prey basis have on the predators. With a view to standardize scientific and conservation activities on the continent and reduce variation, ALPRU has developed a comprehensive procedure to facilitate collection of morphometric data from immobilised and dead predators.

The following diagrams indicate how the bodily measurements of large predators can be determined by means of using ALPRU procedures.  Provision has been made for 47 variables when performing this procedure on a male lion.
 
The complete procedure, followed and developed by the ALPRU, is available at the following website [http://www.uovs.ac.za/alpru] and focuses on a significantly larger number of variables as is the case when measuring only the skull and possibly also the length of the animals.

Only 2 measurements are taken during trophy hunting trips i.e. the skull measurements. The skull is then registered if it is large enough to be regarded as trophy material. If not, then very little will be seen of or done to it.  Imagine the potential loss of data (which could be used for scientific and conservation efforts) incurred if it wasn’t stored in a secure and sensible manner.

With the exception of 8 variables which are only applicable to a male lion’s mane, the ALPRU methods have already proven to be successful when measuring the other large African predators by means of the 39 indicated variables. Example: leopard (P.pardus), cheetah (Acinonyx jubatus), caracal (Caracal caracal), black backed jackal (Canis mesomelas).

The measurements are then documented onto a form (Morophometric Data – Large African Predators) and sent to the ALPRU. 

The data used to measure individual variables of certain species are provided in tables 1 and 2.

At this point you may ask: why is it so important to gather data more comprehensively on the large African predators? It is quite simple. Biological variation as we see it in animals (both wild and domesticated) is the result of two components, namely genetic and environment. The continued existence of an animal population is governed by processes of social behaviour and procreation; thus transmitting genes from two parents to their offspring.

The environmental component on the other hand comprises factors such as climate, nutrition, etc. Differences in environmental factors impacting on individuals, especially nutrition, are important underlying causes for the biological variation regarding mature size of individuals as seen in animal populations. However, the influence of genetic variation is always present. Definite conclusions can only be drawn based on sufficiently large sets of data. Therefore, it is important to measure as many individual specimens as possible.

The measurements of the manes made at six of the eight defined positions on the bodies of two male African lions (an adult and a sub-adult) are presented in Table 2, clearly demonstrating quantitative differences in both length and extent of mane development. This is an important aspect because trophy quality for specific species such as lions can now be assessed quantitatively with a comprehensive range of morphometric data, which may prove invaluable in setting hunting quotas on a scientific basis. Furthermore, predator-livestock conflict and the negative impact it may have on the prey base of predators make it important to determine whether individuals of a population are well developed for their age.

It is envisaged that the comprehensive and non-invasive techniques developed by ALPRU may make it possible to determine if large African predators have been subjected to subnormal growth and development because of factors impacting on the habitat and prey base. In addition to the morphometric data collected on the continent for all available specimens by scientists and the hunting fraternity, specific information on the area, habitat and prey base will be available to formulate integrated wildlife management plans.

This initiative has already drawn a lot of interest since it was launched in 2003. A substantial amount of data and photos, from South Africa as well as other African countries have been received. We trust that this introduction will tickle your interest to use the opportunity presented with this initiative by means of active participation. We would also like to emphasise that this method of measuring the large predators of Africa stretches far beyond the lion only. Each contribution made is greatly appreciated.

For more information on ALPRU and this project, contact us at:


email:        ALPRU.sci@mail.uovs.ac.za
website:    www.uovs.ac.za/alpru
Tel:        +27 (51) 4012210
Fax:        +27 (51) 4012608
Cell:        0836458958

Table 1    Body mass and eight body measurements of five adult specimens of four large African predator species [African lion male (ALPRU00047) and female (ALPRU00050), male leopard (ALPRU00119), female cheetah (ALPRU00110) and male caracal (ALPRU00089)]

Variable
Lion (male)
Lion (female)
Leopard (male)
Cheetah (female)
Caracal (male)
(kg)
Body Mass
177.5
145.0
69.0
50.0
9.9
(mm)
Body length
2730
2618
2170
2195
1040
Tail length
858
820
790
800
274
Tail circumference
228
240
200
190
70
Heart girth
1280
1250
870
750
445
Abdonimal girth
1100
1260
760
703
414
Head length
376
335
290
206
131
Head width
243
222
190
186
95
Rostrum width
91
83
77
48
32

Table 2    Means of six measurements of the length of the mane collected from a sub-adult male African lion [ALPRU00035] and an adult male African lion [ALPRU00047]


Sub-adult male African lion
Adult male African lion
Variable
(mm)
(mm)
Mane, top line
172.5
280
Mane, between ears
162.5
250
Mane, base of neck
205.0
270
Mane, side of neck
192.5
300
Mane, breast bone
135.0
200
Mane, belly
-

70

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