May 2023

Breeding Strategies

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Breeding Strategies

We are very fortunate at the moment to be able to see young lion cubs in the concession. A few days back I was sitting with four of the Shish lionesses and their five cubs, which are now between three and four months old. They are very cute! It is great to watch them running around, playing with each other and giving their moms grief. They even play with the two adult males (the Trichardt males are their fathers). It surprised me how tolerant the males are with the young cubs, even when the cubs jump on top of them and play with their tails.

While we were watching the lions one of the guests noticed that the cubs are much spottier than the adults. I explained that when lions are first born they have faint spots all over their bodies (and particularly around the legs, bellies and on top of the foreheads) and that these spots fade as the grow up. If one looks carefully at the adults, one may still see remains of the spots on their legs and bellies. I elaborated that this aids in camouflaging the youngsters when they are still babies and often left hiding near the den or in the thickets while the adult lionesses go out hunting. Lions cubs are actually quite obedient, remaining at the hiding place while the females go out hunting.

There are quite a few animals whose young are coloured differently to the adults. I gave the examples of young deer, who are often covered in spots so that they blend in better with the environment where they are hidden by their mothers. Cheetah cubs also look different to the adults. They have a distinctive pale mane (or longer hairs) on the backs. The spots on the bellies are much closer together than those of the adults giving their lower halves a darker appearance. They almost look two-toned. The long hairs on their backs are pale in colour and blend in well with the veld grass. It is often said that the baby cheetahs have the appearance similar to honey badgers (which are extremely tough animals often avoided by other predators). This colouration of the cubs aids in not only hiding the babies but also by giving the impression that they are more dangerous than they actually are. Thus, it discourages other predators from attacking them.

Spotted hyena cubs also look very different to the adults when they are very young. Hyenas hide their cubs in dens, which are usually holes in the ground or in caves. For the first two to three months the cubs are a dark brown colour and thereafter only do they start to show their adult spotted patterns. The dark fur of the cubs keeps them camouflaged in the dark dens while they are still young and more vulnerable.

Black-backed jackal pups are also different in colouration to the adults. They do not have the distinctive saddles on their backs when they are young and are much greyer in colouration. They thus blend in better in the grassland habitats that they live in.

Even Blue wildebeest calves look different to the adults. The adults are a bluish, grey-brown colour, whereas the calves are tawny. This tawny colouration allows them to better blend in with the grass.

This discussion opened up further into other breeding strategies that lead to a better survival rate of baby animals. When we look at antelopes, we can differentiate between those which are hiders and those which are followers. In some species when the female gives birth to the young calf, she hides it for a few days. In this case the baby is hidden in thick vegetation and is usually left there until the mother comes back to allow it to suckle.

This is often the case with antelope that live in thicker vegetation such as the spiral-horned antelopes (e.g. kudus, bushbuck, nyala etc). The diminutive antelopes (such as steenbok, common duiker and Sharpe’s grysbok) can also fall into the category of hiders. Once the baby has grown up to the point where it is strong enough and fast enough to follow the mother around, she will then stop hiding it and may introduce it to the rest of the herd. Many ecologists refer to these ungulates that are hidden when they are really young as fawns (particularly with antelopes or deer) or lambs.

Followers have a different strategy. When their young are born it is not long (sometimes only a few minutes or hours) before the youngster is able to stand and follow the mother around. Examples include Blue wildebeest, giraffes, buffalos and plains zebras. Often the followers tend to be animals that live in larger herds or in open grassland habitats. Animals that are nomadic and are constantly on the move often fall into the category of followers. Young animals that are classed as followers (particularly in the antelope groups or ungulates) are often referred to as calves.

This then leads to the concept of altricial versus precocial youngsters. According to the Oxford dictionary the term “altricial” means “(of a young bird or other animal) hatched or born helpless and requiring significant parental care”, whereas the term “precocial” means “(of a young bird or other animal) hatched or born in an advanced state and able to feed itself and move independently almost immediately”.

Hiders, therefore, tend to give birth to young that are more altricial, whereas followers give birth to young that are more precocial. Predators often give birth to altricial young. If we compare lions with wildebeest, lions tend to have much shorter gestation periods than wildebeest do. Lions are pregnant for three and a half months, whereas blue wildebeest are pregnant for approximately eight and a half months. When lion cubs are born, they are blind and helpless. Wildebeest calves, in contrast, are able to stand and move within minutes of being born. The reason for this is that it would be very difficult for the lioness to hunt if her babies remained in the womb until they were more developed and larger in size. Blue wildebeest are considered to be prey species (as opposed to being predators) and their babies would be more vulnerable to predation if they were less developed at birth. Even herbivores that hide their babies when first born have youngsters that are more precocial than, for instance, predators. As a result, many of the predators make use of dens (or hiding places) to hide their youngsters when they are still blind and helpless. This gives added protection to the infants.

On our night-drives we often see scrub hares, usually running in the road in front of the cars. In our area we do not see rabbits. One of the main differences between rabbits and hares is their birthing strategies. Rabbits usually give birth or hide their infants in warrens or holes in the ground and their young are naked and helpless at birth. Hares, in contrast, give birth to their young above ground in a nest called a “scrape” or “form”. Their young are much more precocial and are fully furred and their eyes open much earlier than rabbits. When we look at scrub hares it may lead us to ask how they manage to survive in an area that has many predators (especially because scrub hares are nocturnal and lions, hyenas and leopards also tend to be more active at night). It is not that the scrub hares as individuals survive long, but rather that they are able to breed rapidly, thus allowing the species to continue. Scrub hares do not usually have more than two leverets (baby hares) at a time, but it is maintained that a female can have up to four litters per year.

When we look at animals that are large in size and that live long lives, we find that they tend to have fewer young at a time and tend to spend more time raising and teaching their young. In contrast smaller animals that have shorter life-spans tend to have more young at a time and their young become sexually mature at earlier stage. Ecologists often refer to the term “r and k strategists” when it comes to differentiating between species that give birth to numerous young, numerous times during their lifetime and those animals that have fewer young.

Small animals that live short lives often fall into the category of r-strategists. According to Wikipedia “r-selected species are those that emphasize high growth rates, typically exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood”. R-strategists include many insects, bacteria, cephalopods and small mammals such as rodents and hares. Larger animals tend to be k-strategists, giving birth to fewer young at a time and taking the time to raise or teach those youngsters until they become adults. Elephants are prime examples of k-strategists.

Another survival strategy of animals, relating to their breeding, is the seasonality of their birthing. Some animals in the bush breed seasonally whereas others give birth any time of the year. Many of the seasonal breeders do so in order to take advantage of the abundance of resources during the summer months. Animals such as impalas, wildebeest and zebras usually give birth in spring when there is an abundance of lush, green grass, which helps the mothers to produce milk. These animals tend to have specific rutting or mating periods in order to ensure that their youngsters are born at a time that the environment is more conducive to the survival of their young. Many bird species lay their eggs during the spring and summer months. This is because spring and summer are the times that the insect numbers are at their greatest and when the grass comes into seed. African wild dogs tend to den during our winter months. It is thought that this is the case because when the pups are just getting ready to leave the den and run with the adults it is the time that the impalas (the main prey source of the dogs) are heavily pregnant and, therefore, slower, or have already given birth (providing a great abundance of vulnerable prey). Not all of the large mammals give birth seasonally. Elephants, giraffes, kudus, lions and leopards (amongst others) are examples of animals that can give birth at any time of the year and are not seasonal breeders.

Species that exhibit seasonal breeding usually give birth round about the same time (often within a very limited time period). A great example of this is the impala. Impalas have a set rutting period (April/May) in southern Africa. The lambs are generally all born within a few weeks of each other. This results in an abundance of babies of that species at that time. This means that hungry predators may catch and kill a few of the babies and they are then full, only having to hunt a few days later again, when the remaining babies have had time to grow a little bit and become more active and faster and thus able to evade the predators better. Impalas, therefore, saturate the market with babies. Kudus, in contrast, give birth intermittently throughout the year. This means that a predator that finds a baby kudu will kill it and feed on it and then may potentially find another new-born kudu when it becomes hungry again. Fortunately, kudus tend to live in thicker vegetation where they are able to better hide their babies. Because of the open habitat that “plains species” live in these animals often give birth seasonally, whereas those animals that live in more concealed habitats do not.

Lionesses also tend to give birth within the same time period. This is not as a result of living in any specific type of habitat, but rather based on convenience. Lionesses within a pride often come into oestrous round about the same time. This means that the cubs from different females are all born at the same time. It is much easier to raise youngsters of the same age together and there is less competition between older cubs and younger cubs (the older cubs would have a distinct advantage in obtaining milk / food because they are bigger and stronger and therefore more dominant over their younger siblings). The five cubs that we are presently seeing with the Shish Pride are from two litters. If one looks very carefully one can see that two of them are slightly smaller than the other three, although the size difference is really negligible and the larger cubs, therefore, are not dominant over the smaller ones.

Predators tend to have a very high mortality rate when they are babies. The young cubs/pups are very vulnerable and are easily killed by other predators (particularly when the adults are out hunting), by disease, from lack of nutrition, from poor weather conditions or from foreign males (males who are not their fathers) who enter into the area and find them.

Brian Rode
By Brian Rode
Senior Field Guide