African Ecology & Conservation Predators Unit 2

African Ecology and Conservation African Predators Level 4 Unit 2

African Ecology & Conservation (African Predators)

Level 4

UNIT 2 Approximate learning hours: 15

Biology and Ecology of African Predators

1


Learning Outcome At the end of this unit you should be able to:

2.0 Outline, explain and compare the basic biology and ecology of African predators

Bibliography: page 17

Selected references: unit 1

Internet resources: page 18 and unit 1

2


2.0 Biology and Ecology of African Predators 2.0 Outline, explain and compare the basic biology and ecology of African predators

Introduction

Unit 2 investigates the differences between the biology and ecology of African predators. An example species from selected groups of predators named (table 1) in the unit is given as a starting point for self-directed research and learning to support the assignment.

African predators identified in the unit are the big cats, small cats, canids, hyaena, marine predators, birds of prey and reptiles. Each example is outlined according to:

i. Their distribution within or around the African continent ii. Physical appearance iii. Lifespan iv. Habitat v. Diet vi. Key aspects of behaviour vii. Reproduction viii. Parental care ix. Social grouping x. Competitors, threats and predators xi. Conservation status

For each example species, the habitat type(s) should be identified in detail with reference to unit 1.

3


Table 1 African Predator Groups Predator Group African Big Cats

African Small Cats

African Canids

Hyaena Family (Hyaenidae)

Marine predators

Birds of Prey

Reptiles

Species or General types The African Lion (Panthera leo) The African Leopard (Panthera pardus) The Cheetah (Acinonyx jubatus) Serval (Leptailurus serval) Caracal (Caracal caracal) African wildcat (Felis sylvestris lybica) Black-footed cat (Felis nigripes) African golden cat (Profelis aurata) Sand cat (Felis margarita) Jungle cat (Felis chaus) African Wild Dog (Cape Hunting Dog/ Painted Dog) (Lycaon pictus) Ethiopian Wolf (Canis simensis) Black-backed Jackal (Canis mesomelus) Golden Jackal (Canis aureus) Side-striped Jackal (Canis adustus) Cape fox (Vulpes charma) Bat-eared fox (Otocyon megalotis) Pale fox (Vulpes pallida) Fennec fox (Vulpes zerda) Rüppel’s fox (Vulpes ruppellii) Brown hyaena (Hyaena brunnea) Striped hyaena (Hyeana hyaena) Spotted hyaena (Crocuta crocuta) Aardwolf (Proteles cristata) Sharks (including Great White, Tiger and Mako) & other species of carnivorous fish Killer whales (Orca) Many other fish-eating whales (Minke, Blue, Sperm, Brydes) Dolphins (Bottlenose, Indo-Pacific Humpbacked, Long-beaked Common) Seals (Leopard, South African/Cape Fur Arctocephalus pusillus pusillus) Vultures, Eagles e.g. Martial Eagle (Polematus bellicosus), Falcons, Hawks and Buzzards, Owls Nile Crocodile, West African Dwarf Crocodile Nile Monitor lizard, Puff Adder, Black Mamba Spitting Cobra, Cape Cobra, Boom Slang (Tree snake), Gaboon Viper, Egyptian Cobra Carpet Viper, Eastern Green Mamba

Example Species Panthera pardus

Leptailurus serval

Lycaon pictus

4


The Big Cats The term “big cat” is not a scientific or taxonomic classification but used informally to describe the larger species of cats, typically lions, tigers, and leopards. Like all other cats, the big cats of Africa (lions, leopards and cheetah) are all part of the Family Felidae, which includes thirty-four other species of cat found around the world (some also in Africa).

The African Leopard

Population distribution

Leopards occur in most areas with annual rainfall above 50 mm per year, and even in areas with less than this so long as a waterway is available (e.g. a river). Leopards are the only cat species in Africa to be found in both rainforests and desert habitats. Their presence near or on the outskirts of major cities indicates their adaptability to changing environments. However, in some areas of Africa (particularly Western Africa) they have become rare and even completely disappeared from some parts.

Habitat and Physical appearance

Similar to their wide range in habitat preference, leopards show great variation in their appearance and behaviour.

The typically yellow background coat colour varies from pale

cream to dark gold or ochre colour, and these differences are associated with habitat type (e.g. savannah leopards are more orange coloured than the pale desert leopards but the rainforest leopards are darker than both savannah and desert leopards.

Black leopards (figure 1) occur more often in forested areas than other habitats. Morphological differences also include adult body weight, which varies considerably (from 30 – 60 kg) and is thought to reflect typical prey species available (i.e. leopards are smaller in areas where prey is smaller, and vice versa).

5


Figure 1 Black leopard (author “Quilimon”)

However, even small leopards are capable of taking relatively large prey as leopards have particularly large and strong skulls and jawbones. These allow for attachment of powerful muscles providing significant bite strength. The scapula (collarbone) of leopards is adapted for climbing.

Lifespan

Leopards in the wild live approx 10 – 15 years but in captivity they have been known to live up to 20 years (generally 12 – 15 years).

Diet

Leopard versatility extends to their prey, which may include anything from dung beetles up to adult eland (a large antelope species that may weigh 900 kg). Rodents, birds, small and large antelope, hyraxes and hares and other insects are also included in the widely varied diet of leopards. Primates, including chimpanzees are also taken, if the opportunity arises.

When leopards are able to consume medium sized antelopes they may only need to eat once every week. Males may consume approximately 3.5 kg of meat per day. Females with cubs will need to eat more regularly and in greater quantities than a female without cubs. 6


Key aspects of their behaviour

Adaptations of the leopard’s behaviour are observed according to the habitat, prey availability and competition.

One of the primary reasons leopards are able to co-exist with other

predators in so many different habitat types is their ability to change the diet so that they do not compete directly for the predominant food source of other predators.

Moreover, the ability of leopards to hide their kills in trees, which requires great strength as some carcasses weigh 2 – 3 times as much as the leopard, means that they do not risk losing their prey to other predators. In areas where there are few trees in which to hide carcasses, leopards use their strength to drag carcasses for long distances to hide them in rock crevices or dense vegetation.

Being able to climb trees quickly and efficiently also provides leopards with an escape route if faced with aggressive confrontation from another predator, and a safe place to rest without being disturbed. Another factor in the success of leopards may be due to their behaviour of attacking smaller predators which may be competing for the same food resources, and they will also kill the cubs of large competitor species such as lion, cheetah and hyena. Most activity occurs at night for leopards; they will hunt primarily in the dark although daytime hunting is also observed.

Reproduction

Leopards do not have a particular breeding season although, as with lions, peaks in births may occur simultaneously with the peak in birth rate of their preferred prey species. This is likely to mean that females with cubs do not suffer from lack of food availability. Female leopards are in heat for approximately 1 week and gestation (pregnancy) lasts approximately 95 days.

Most litters range between 2 – 3 cubs but nearly half of all cubs do not survive their first year. A female may have a litter of cubs every 15 – 24 months, depending on litter survival and prey availability. Females can breed from around 3 years of age, while males may start breeding earlier at approx 2 years, but both sexes can breed for the majority of their life thereafter (up to 19 years has been observed in captivity).

7


Parental care

Cubs will remain with their mother until they are approx 13 – 18 months old. When prey is abundant, dispersal of young may be delayed.

Social grouping

Leopards are solitary once they reach adulthood.

After leaving their mother siblings may

remain together for a few months, presumably to assist in adapting to life on their own.

Competitors, threats/predators

Leopards will be scared off their prey by other scavengers, including lions, hyenas and occasionally other leopards. Their elusive and secretive nature means that they are often able to hide from such threats but competition for territory or prey may become fierce during drought or other times of low prey availability. Despite leopards being able to adapt to changing environments, including those associated with human settlements, their population numbers are drastically reduced when they occur in close proximity to humans.

Exploitation and population fragmentation are key threats to leopards. Leopards were once targeted by the fur trade and this had a devastating effect on their population in some areas. However, changing public opinion on fur and the introduction of legislation banning the trade in certain species has meant that the fur trade has dramatically changed and is no longer such a threat to leopards.

Nonetheless, they are still poached and hunted for their fur, and even some legal hunting is permitted in some countries.

Leopards are also targeted by local human populations as

threats to livestock or human life and may be easily trapped by using poisoned bait or placing traps (lethal) along frequently travelled boundary pathways used by leopards to mark their territory. Loss of habitat and natural prey base in areas cultivated by humans is also a major concern for leopard population stability.

8


Conservation status

The leopard is classified as “near threatened” by the IUCN and their population stated as “decreasing”. However, leopard population counts are not always consistent and there is debate about the current status of the leopard within countries, and varies widely between different countries. A quota for the number of leopards that may be hunted legally has been enforced by a number of countries, and these leopards are typically shot for their skin or as trophies by sports-hunters. This quota system is designed to ensure that only a sustainable number of leopards are removed from the population in this way each year. The leopard is typically well protected across its habitat range although the killing of “problem” animals is also generally permitted.

9


The Small Cats

Serval (Leptailurus serval)

Description Servals are long-legged felids with long necks and distinctively large ears (see figure 2). They have pale yellow coats with black spots on their sides and stripes across the neck, shoulders, lower legs and tail. Servals have relatively short tails (approx. a third the length of their body). They are approximately 60 cm tall (at the shoulder) and weigh around 10 – 12 kg.

Figure 2 Serval – note the large ears used for detecting prey in the tall grass

Melanistic (black) Servals have been observed and there is quite a lot of variation in the normal yellow and black colouration as well (some have small freckle-like spots while others have much larger spots and stripes).

The distinctive characteristic of Servals is their ability to jump metres up into the air to catch birds on the wing, or to pounce on prey up to 4 metres away. Servals are specialists in this regards, as they rely on their use of height rather than speed or power to catch their prey. The enlarged ears reflect their keen sense of hearing and their strong curved claws allow them to hook rodents hidden in thick grass.

10


Habitat and distribution

Servals are found in moist areas with tall grass and tend to occur south of the Sahara. Although they have been found in more arid areas of Africa (e.g. North Africa, areas of Southwestern Africa, Ethiopia and Somalia), they are more common in sub-Saharan countries. Likewise, Servals may also use alpine grasslands and the verge of rainforests, but they have not been found in the dense rainforests of Central Africa. The strong association between Servals and waterways means that their distribution is very localised.

As long as there is sufficient moisture and shelter, Servals can even adapt to cultivated land, preying on small birds and mammals. However, Servals may acclimatise to living near human settlements by becoming nocturnal, whereas in areas without human disturbance they are considered to crepuscular (active most at dawn and dusk).

Diet Generally, Servals tend to specialise in rodents and are well adapted to hunting in the long grass of their habitat. Their ability to leap vertically from a standstill (figure 3), combined with their lack of fear of water, means that they can consume aquatic, flying and terrestrial (land-based) prey species with efficiency.

Figure 3 Serval jumping – note the extreme elongation of the cat’s body. Also, note the stripes along the legs and neck area (author Steve Jurvetson).

11


Their large ears allow them to detect and locate their prey without necessarily seeing them, and even prey underground can be detected by the serval’s acute sense of hearing. Servals will also supplement their diet with amphibians, insects and reptiles.

Reproduction and lifespan

Servals may live up to 19 years of age, and can begin breeding at 18 – 24 months. There is no specific breeding season for Servals, although peaks in birth rates are observed in the wet season when prey populations are at their highest density.

Gestation lasts approximately 73 days and Servals normally give birth to 1 – 3 kittens. These kittens are dependent on their mothers until they are 6 – 8 months old, but mothers may tolerate newly independent juveniles) in their home territory for up to 2 years.

Sociality Although Servals are typically considered solitary animals, it seems that adult Servals will tolerate overlapping home ranges, and may even hunt together.

However, typically it is

mother-daughter pairs that move and hunt together, whereas males may tolerate other males in his territory but will not normally be seen with other animals (except when with a female for mating). In some studies, up to 5 male Servals have been found to share the same area.

12


Canids

The Canidae are members of the dog family and there are numerous species in Africa.

African Wild Dog/Cape Hunting Dog/Painted Dog (Lycaon pictus)

Description

African wild dogs are not domestic dogs that have gone wild (feral) but are a distinct species that split from the Canis ancestry (to which the dog, wolf and jackal all still belong) several million years ago. Remarkably, this difference is not just taxonomic but has resulted in a physical difference: African wild dogs do not have a dewclaw, unlike other dogs.

This

dewclaw (the fifth toe on each front foot) is completely missing in African wild dogs.

Another defining feature of African wild dogs is their unique coat pattern and large rounded ears (see figure 4). The coat pattern of each African wild dog is unique to that individual and can be used by scientists to identify animals within a pack.

Figure 4 Image of an African Wild Dog. Note the multi-coloured coat pattern and large round ears. (photo author Philip Gabrielsen).

13


African wild dogs are medium-sized predators of splotchy yellow, tan, black and white colouring, with a bushy tail. The white tip at the end of their tails is thought to act as a signal to others or way for pack members to follow each other in the long grass. They typically weigh around 17 – 36 kg and are 60 – 80 cm high at the shoulder. African wild dogs are highly intelligent and have a comprehensive communication repertoire consisting of various sounds, calls, body language and scents.

Habitat and distribution African wild dogs were once widespread throughout sub-Saharan Africa, but are now declining rapidly. They are restricted to small isolated populations around central, east and southern parts of Africa (figure 5). The largest population is found in sub-Saharan Africa.

African wild dogs typically occur in arid areas and the savannah. However, they may also be found in woodland and mountainous areas as long as there is sufficient prey.

Figure 5 Map of the African continent showing the distribution of African wild dogs (shown in red; author “Nrg800”).

This species is a remarkable traveller, covering vast distances and being excellent endurance runners. However, when a litter is born in the pack, the pack will settle in a smaller territory and not resume their nomadic lifestyle until the pups are young adults.

14


Diet

Gazelles, antelopes, warthogs, rodents and birds will form the major part of the African wild dog’s diet. Being carnivorous hunters, they will consume a variety of animal tissues, and may scavenge on carrion. The hunting system of African wild dogs is quite remarkable and highly organised with a ceremony of playing, circling, vocalising and touching used to initiate each hunt. Once the pack is sufficiently excited by this ceremony, they will begin exploring their territory for potential prey.

Upon locating a prey animal the pack co-ordinate their movements to chase the prey animal until it is exhausted. The pack does this by co-operating so that as one pack member tires and slows down, another takes over the chase. They are also excellent at cornering, surrounding or cutting-off the escape route of prey animals.

African wild dogs can chase their prey for very long distances and at speeds of up to 35 miles per hour. Due to their co-operative and efficient hunting strategy, they are among the most successful of larger African predators, with very few prey animals escaping once they have been targeted.

Reproduction and lifespan

These dogs can live between 10 and 12 years and will breed seasonally, just like domestic dogs.

The pups are typically born in seasons when prey is most abundant.

Females are

pregnant for approximately 11 weeks and will give birth to litters of 10 – 12 pups. The pack will share in the rearing of the alpha-female’s pups and during the first 3 weeks of lactation, when the pups are entirely dependent on her milk, the female very rarely leaves the den, and only for short periods of time. Therefore, she relies on other members of the pack to bring her food.

Typically, it is only the alpha male and female (leaders) that will breed. Subordinate pack members provide support for the rearing of the alpha female’s pups. However, studies have shown that the attitude of the alpha female can vary considerably towards the pups of other pack members. Some alpha females will kill any other pups, while others will tolerate them or even fully accept them.

15


Once pups are older than 3 weeks they can be moved out of the den and the female can leave the den to obtain food or nurse the pups above ground. Pups are weaned at around 8 – 10 weeks of age. They no longer require the safety of a den after 3 months. Members of the pack will regurgitate food for the pups to supplement their milk diet until they are weaned.

Sociality African wild dogs possess a complex social system and live in packs of between 6 and 20 individuals. These packs are highly dynamic with pack stability being lower than that of a lion’s pride as African wild dogs suffer high mortality rates (both as adults and pups). This is thought to be related to their high energy-demanding hunting strategy, and their vulnerability to other predators.

Very little aggression is observed between pack members but they all seem to “know their place”.

They have a wide range of vocal signals, ranging from bell-like contact calls,

twittering, and whining to short alarm barks and rallying howls. African wild dogs exhibit complex greeting rituals and all pack members will be involved in the care of pups.

Unlike lions that will tolerate temporary separation of individuals or sub-groups from the pride for periods, the separation of any African wild dog pack member is a very stressful event for the whole pack. Apart from adults who may stay behind to guard pups while the rest of the pack hunts, adult African wild dogs are rarely left alone. When separated, individuals will produce bird-like calls to attempt to locate and re-unite with the pack.

Completion of unit 2.

16


Bibliography

Macdonald, D. & Loveridge, A. 2010. The Biology and Conservation of Wild Felids. Oxford University Press (Oxford).

Mills, G. & Harvey, M. (2001) African Predators. Struik Publishers (Cape Town, South Africa).

Sunquist, M. & Sunquist, F. (2002) Wildcats of the World. University of Chicago Press (Chicago, Illinois).

Wilson, D. E. & Mittermeier, R. A. (eds.). (2009)

Handbook of the Mammals of the

World. Vol. 1. The Carnivores. Lynx Edicion (Barcelona).

17


Internet resources in no particular order

African Wildlife Foundation: http://awf.org

ARKive http://www.arkive.org/

Biodiversity Library http://www.biodiversitylibrary.org/

Bird Life International www.birdlife.org/datazone/species/search

Convention

of

International

Trade

in

Endangered

Species

(CITES):

http://www.cites.org/

Global Species http://www.globalspecies.org/

IUCN

Cat

Specialist

Web

Portal:

www.catsg.org/catsgportal/cat-website/20_cat-

website/home/index_en.htm

UCN Red List (information on all threatened species): www.iucnredlist.org/

Kruger Park guide to reptiles and snakes: www.krugerpark.co.za/Kruger_Park_Reference_Guide-travel/african-reptilesguide.html

Marine Bio Conservation Society http://marinebio.org/oceans/creatures.asp

Marine Species Identification Portal: http://species-identification.org/index.php

Predator Conservation Trust: www.predatorconservation.com

The Peregrine Fund www.peregrinefund.org/subsites/explore-raptors-2001/

18


19