Reproduction and offspring
Lions have no particular breeding season, and often synchronize
breeding, especially after a pride takeover, raising the cubs
communally. Birth peaks have been observed in Kruger (February – April)
and Serengeti (March – July) National Parks related to seasonal weather
patterns and prey availability [36], [64].
Male lions become sexually mature at around 26 months old [36], but
unlikely to breed before the age of four or five, primarily due to a
lack of opportunity until they are large enough at around this age to
take over a pride and therefore its breeding rights. At Phinda reserve
in South Africa introduced males sired cubs at 27 months. The mean age
of first conception in Kruger National Park is 48 months although 29%
sired cubs at 40 months [65]. Breeding by some males was delayed until
54 – 60 months. Males as old as 16 can produce viable sperm, but
reproduction probably ceases after their pride tenure is lost.
Females at Phinda conceived for the first time at 32 – 33 months [66]
with most lionesses having given birth by the time they are four years
of age [18]. Females can breed until they are c. 15-years old, but
reproduction usually starts to decline at 11 years. A lioness in the
Kgalagadi Transfrontier Park gave birth at 19 years old [67].
Onset of oestrus is in response to within-pride mechanisms such as
oestrus in pridemates as well as loss of cubs from infanticide at pride
takeovers [18], [68] - [69]. Lionesses are polyoestrus, oestrus lasting 4
– 7 days with intervals between periods of a few days up to more than a
year (average 55.4 days). They have a post-partum oestrus but do not
conceive if the litter survives. If the litter is lost a new one may be
produced within four months [70].
When a litter is raised to maturity the mean litter interval is 601.5
±119.8 days at Phinda [66]; In Serengeti NP the mean was 20 months
(range 11 – 25) [71] when a litter was raised to maturity and a range of
4 – 6 months if it lost.
Courtship may be initiated by either member of the pair who remain
close during the oestrus period. The female usually invites copulation
by lordosis. There is little competition amongst pride males during
mating. Instead of fighting to be the first to mate a female in oestrus,
a male will follow her around very closely at the first signs of
oestrus onset. Other males keep their distance unless there is a clear
size difference, in which case a larger male may fight a smaller one.
This works because females have a long oestrus period and copulate many
times during that period. Males may lose interest before the end of an
oestrus period, giving patient males a chance. Also, due to the common
synchrony of reproduction there is often more than one female in heat at
any one time. A lioness mates up to 100 times per day with an average
interval of 17 minutes (range 4 – 148), each mating lasting for c. 21
seconds (range 8 – 68) [18], [70], [72] – [73].
During the periods between copulation the pair may lie down next to each
other or walk a short distance. The male may gently stroke the female
with his tongue on the shoulder, neck or back to initiate copulation.
Towards the end of copulation the male may gently bite the back of her
neck. During copulation the female may purr loudly.
Male cats have spines on their penis to cause slight trauma to the
vagina upon withdrawal. The resulting pain triggers ovulation [56]. It
may also explain why females bare their teeth at males during mating.
The penis is also mobile and can be pointed backwards or moved from side
to side for scent spraying. Conception occurs on the 4th day of
oestrus with a conception rate per cycle of 38%. The level of nutrition
influences both fertility and litter size [70].
Gestation is between 100 – 120 days. Just prior to cubbing the female
will move away from the pride and give birth in a well hidden lair. The
typical number of cubs in a litter is three (range one – six). The
postpartum litter size is virtually the same to litter size in utero
with the sex ratio at parity [18], [66], [70] – [71], [75]. Cubs weigh
c. 1.65 kg at birth gaining c. 106g per day in the first four weeks of
life [76].
The female will only rejoin the pride with her cubs if the cubs already
established in the pride are not more than 3 months old. The reason for
this is that all lactating females suckle cubs indiscriminately,
showing only limited favouritism to their own offspring. Therefore young
cubs would suffer in competition against cubs over 3 months old. This
collaborative behaviour probably stems from the close genetic
relatedness among a pride’s females (each sharing c. one seventh of
their genes with pride mates [62]), each lion is enhancing her own
genes’ success by helping raise her sister’s offspring. Cubs suckle
regularly for the first 6 – 7 months, the frequency declining
thereafter. Cubs remain with their mother for 21 – 24 months up to 30
months [18], [70], [76] – [77].
Cub mortality is high; in Kruger c. 50% died [78], a similar figure was
given for Nairobi National Park [19]. In Etosha National Park and
Mashatu the figure was lower at 40% [79] – [80] whilst a figure of 67%
was given for the Serengeti [18]. There are many reasons for mortality
in cubs; first, teething is painful and weakens the cub so that many die
during this time. Disease is an important factor in cub mortality, as
is abandonment; mothers often get absorbed by some activity and forget
for a while that she has cubs. A male taking over a pride may kill cubs
under a year. Cubs are predated upon by other carnivores as well as
buffalo. Finally, cubs are at the bottom of the food chain; a mother
will let her cub starve if she’s hungry and will not slow her pace for a
cub older than five – seven months, which once left behind has little
chance of survival. As many as 80% of cubs will die before the age of
two years.
Source:
http://lionalert.org
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