There has been so much talk recently about the birthing season of the new impala lambs. You would have recently read Patrick’s blog about this exciting time with lambing season. I have always said that the turn of summer is my favourite time in the bush, and even more so with all the births of new animals.
Almost every herd of elephants we are seeing at the moment includes a tiny calf sticking side-by-side with its mom. The same can be said for the dazzles of zebra and giraffe journeys.
One striking contrast I often speak about during this time is the gestation periods of predators and prey. Take, for example, a lion versus an impala. A lion weighs about five times that of an impala, stands much taller, has a robust build and can easily hunt down an impala. When looking at the two animals side-by-side, there is no comparison as to which looks more developed and powerful.
There is a stark contrast between these two animals, and there is no question about which is bigger and more dominant.
That being said, it’s surprising to find out that the gestation period for a lion is 3.5 months while that of an impala is 6.5 months – almost two times more than a lion! What’s the reason for this? Well, knowing nature and how everything happens for reason out here, there is a proper justification for how this works.
Lion cubs
We’ll start with the animal on top of the food chain – the lion. Arguably the biggest and most dominant predator in Africa. With its powerful strength and large size, it comes as a bit of a shock that it only takes 3.5 months (around 110-120 days) for a lion to develop in its mother’s womb.
Lion cubs have the huge advantage of protection from their pride. The primary responsibility of adult males is safeguarding the females and cubs. The females play a large role in looking after each others’ cubs and even allo-suckling. This mutual suckling and communal care of any cub of the pride by any female reduces the chances of mortality for all cubs.
The gestation period is very quick since lionesses need to hunt to survive and provide for their pride. They would be severely disadvantaged if they were weighed down by heavy pregnant bellies for extended periods. As a result, the cubs are underdeveloped at birth – they are blind, weak and helpless. The term we use for this is altricial.
Plus the added risk of taking the hoof of a zebra to the abdomen during a hunt could prove to be fatal to both mother and unborn cubs.
At this stage, the cubs rely completely on their mothers for everything and are kept in hiding while their strength grows enough to join the pride and hold their own.
Cubs can follow their mothers at about three months of age and are weaned by six or seven months. They begin participating in kills by 11 months but cannot properly survive on their own until they are two years old. This is the converse to their prey.
Impala lambs
As impala are herbivores and only need to eat vegetation to avoid starvation, a pregnant belly does not impede their ability to get nutrients and there is no need for them to hunt. The extra time in the womb allows the lambs to be born with well-developed muscles, so they can move and see immediately once they drop. The term used for this is precocial. The reason the lambs need to be born so well-developed is that they immediately must be able to run and escape from predators.
Soon all the lambs are found lying together with their mothers not too far away, what we call a “nursery”.
The mothers keep feeding and communicating with the lambs by grunting. The youngsters drink only the milk their mothers produce for the first three weeks. This milk is filled with colostrum which helps build up the immune system. After these three weeks, they supplement that milk by eating leaves and grass. Between four to seven months the impala is completely weaned, and within two years the females are mature enough to have their own offspring.
Within the first thirty minutes, the lambs can stand and thirty minutes later they can run alongside their mothers – unlike the lion cubs who cannot see or hear anything for the first week.
There is a reason for everything in nature
One of the best things out here is knowing that each animal species has evolved and changed to fit the habitat and increase its chances of best survival. We often look at the physicalities of animals – a giraffe’s long neck; an elephant’s dexterous trunk; a kudu’s massive ears – but there is so much happening internally that we do not see. These internal phenomena, such as gestation periods that best suit each animal species perfectly, are the reason why species do as well as they do. In other words, there is a reason everything happens the way it does in nature.
An interesting gestation comparison Robyn. Both have a successful strategy if in balance. Would Impala and lions for that matter not adapt this strategy should they be under pressure. Pressures like excessive predator vs herbivore numbers, poaching etc?
An interesting concept of gestational time frames that I had not previously thought about…but it makes so much sense. Nature is amazing in so many ways!!
that was an amazing and informative post Robyn – I learned a few new things today. Nature is always amazing in its design to suit purpose and function – incredible. As intelligent as humans are, we still can’t even come close to what is already occurring in nature.
Thanks, Kylea! I agree with you – the intricacies of nature are far beyond what we can imagine.
An interesting comparison. It all makes perfect sense – none of us is smarter than nature, that’s for sure!
A very interesting blog, Robyn.
Nature is amazing, indeed and takes care of all the different aspects and needs, or rater, develops them.
Thanks Robyn for the information on the gestation periods for the impalas and lions. Nature is indeed very smart. We only need to pay attention to improve our understanding.
Thanks, William. Fortunately, there are a plethora of studies and observations at the moment diving into the phenomena of these animals. These, along with paying attention to their behaviours, will help greatly in improving our understanding!
Hi Robyn, you all have given excellent behavioural lessons! There also are semi-precocial and semi-altricial animals. Birds offer various examples, such as gulls and herons respectively. Gulls chicks are nidiculous can’t feel alone properly and herons chick’s eyes are open immediately birth. Passerines are precocial and ducks are altricial. Lovely pictures as always, who is that gorgeous lion?
Thanks for that information, Francesca! Extremely interesting. That lion is one of the Birmingham males from 2019.
Very interesting comparison Robyn. As you say there is a reason for the different gestation time. Both animals are beautiful and perfect in their own right. Understanding nature is the understatement.
Ingenious, indeed!
Interesting insights, Robyn. It’s lack of downtime in pregnancy (lioness) vs. lack of downtime once born (fawn). Is there any advantage to a lioness in having cubs quickly in terms of protecting the cubs from predation by male/other lions? Maybe the lioness needs to have cubs quickly while the mating male lion coalition is still in charge?
Hi Alex, I do agree with you that by having a fast pregnancy and with the lion cubs being born quickly, they will have a longer period of time to be protected by the coalition who sired them. Coalitions change every three years or so, and by the time the cubs are around three years they are able to leave the pride. So by having a short pregnancy it means that the cubs are able to spend as much time growing with the protection of those males as possible. Lion cubs are definitely at a disadvantage if they are much younger when new males take over. The short pregnancy also means that one littler of cubs doesn’t make it, it won’t be long before the females can produce a new litter.
That’s another interesting point that 3 years to independence for a cub also = avg 3 years length of a male lion coalition. Another smart touch from Mother Nature!
Fascinating gestation comparisons Robyn. I had not thought about the differences after birth quite this way, and the reason for the importance. I was aware of the need for Impala lambs to be able to stand quickly and be able to move with the herd considering there’s no real protection by the mother or herd in contrast to lion births. Your article made me think of elephants who have a 22 month gestation period, perhaps the length insuring their calves are fully developed and ready to go very quickly after birth.
Hi Denise, the gestation topic for elephants is fascinating as they have the longest pregnancy period of any living mammal. Baby elephants develop slowly in the womb because of their physical size but also because of the size of their intellect. It is thought that the long gestation period allows for the full brain development of elephants. Calves are born with complex cognitive skills and can immediately sense how to survive in their environment and interact with the herd.