While on an evening game drive recently in Kenya's Maasai Mara safari guide, Joshua Loonkushu, filmed a lion stalking across the savannah. As if in slow motion, the big cat tentatively approached its target – each step: a calculated move to edge closer in silence. But the target was neither prey nor rival. This lion had set its sights on a lioness who lay fast asleep on a gravel road.

"As he got to the lioness, he bit her!" Loonkushu explained to Latest Sightings. "It took the lioness exactly two split seconds to go from fast asleep to be in defence mode and ready to attack." In response to the unprovoked ambush, she snarled and swiped at the male who brushed off her retaliatory blows and took to roaring assertively a few feet away.

So what's up with this aggressive wake-up call? While the behaviour seems almost playful, "this interaction is no laughing matter," explains Dr. Paul Funston, Southern Africa Regional Director for Panthera, the global wild cat conservation organisation.

A lion pride is ruled by a dominant male (or group of males) and there is always risk of a coup from rivals. "When male lions take over a new pride they can be extremely insistent on mating with any adult female that they assume should be reproductively active," Dr Funston explained to us via email. It's possible that this male had been courting the lioness for some time and became aggressive when she refused his advances. "In extreme cases of male frustration and exertion of dominance, lions will even kill lionesses that refuse to mate with them."

Lion pride dynamics can be complex. A typical pride is made up of six or so related females and their dependent offspring. When males mature and leave their family group, they often form coalitions and use force to claim sovereignty over a pride. This can result in bloody battles with existing pride leaders as well as the inevitable killing of any young cubs. Cubs present a major obstacle to new males taking over a pride as the big cats will be looking to sire their own offspring as soon as they can. Mothers are unlikely to mate for the 18 months that it takes for cubs to mature, but they will become reproductively active soon after cubs are lost.

Takeovers usually shake up the social relations in a pride and Dr Funston has witnessed lions and lionesses using naptime to their advantage, "I have not seen a male sneaking up to a sleeping lioness before, but I have once seen a lioness sneak away from a male that was following her closely (consorting) only to rush up to another male and allow him to mate with her," he explains.

The lioness in this pride may find herself in trouble if she choses to ignore the advances of the new pride leader. "I imagine that the male roared right next to the female to impose his dominance and strength and signal to her and others that this is now his pride and that the females are thus expected to mate with him and sire his cubs," Dr Funston adds.