Adult elephants are too massive to draw the attention of an average lion pride on the hunt, but a tiny calf unaccompanied by mom is a potential meal these predators are unlikely to pass up. During a recent visit to South Africa's Kruger National Park, tourist Jill Mathews watched – with a good measure of astonishment and shock – as a pride of lions ambushed a young elephant that had become separated from its herd. The cats' attack was momentarily thwarted, however, by an intervention from another mega-herbivore: enter the buffalo cavalry.

The action took place on a recent afternoon at Klopperfontein Dam in the north of the park. The summer heat had dried up most of the water in the dam, so Mathews arrived to see a smattering of buffalo, zebra, impala and elephants milling around in search of the last pockets of moisture. Also in attendance: a pride of lions surveying the scene undetected on the shaded rocks above the dam. Anticipating a hunt later in the day, Mathews decided to return in the afternoon.

"At 17:15 we arrived back at the waterhole, to find the lions still where we left them earlier," Mathews told Latest Sightings. "We felt a sense of anticipation, knowing that the lions were strategically positioned for an attack on anything that walks too close."

Nobody expected, however, that a lone elephant calf would be the animal to stumble too close. The lions worked quickly: they staged an ambush and pounced, toppling the young elephant and rendering it helpless. "Watching all of this happen, our hearts were pumping!" Mathews recalled.

As the pride closed in, the calf's fate looked sealed ... which is when things took a turn for the unusual. Attracted by the distress calls of the elephant, a herd of buffalo moved in to investigate. The brawny grazers rushed at the lions – much like they would if protecting one of their own – forcing the cats to retreat and allowing the downed calf a chance to clamber to its feet and escape. "I haven't seen this before, but I'm sure the buffalo were reacting as though it was a fellow buffalo being attacked," explained Dr Luke Hunter, President and Chief Conservation Officer for global wild cat conservation organisation, Panthera. "This kind of herd defence in the face of lion attacks by buffalo is common."

The calf's buffalo-aided escape was probably short-lived, however. The lions caught up with it moments later to launch a second attack – and this time, the action took place in thick bush. "The sighting ended with the large pride of 15-18 lions seizing the baby elephant. We presume that they finally succeeded in killing it," said Mathews, who was unable to witness the final outcome.

Further north, a similar case of cat-vs-calf played out in Kenya's Samburu National Reserve (this time it was the calf's mom who saw off the threat at the last instant):


 

Reports of lion-on-elephant attacks are rare in the scientific literature, but it's safe to assume that when young calves begin to stray from their mother's side to explore and test out different foods, some will fall victim to hungry predators. "Generally it's uncommon but it can happen often in some systems and circumstances," Dr Hunter explained.

Aside from yearling calves, or elephants already injured by poaching or weakened by drought, the behemoths are mostly safe from prowling lions. However, there is at least one pride on the floodplains of Botswana's Okavango Delta with a penchant for hefty meals.

The 30-strong Savuti lion pride (named after the marsh in which it reigns) is well known by photographers and wildlife filmmakers for one reason: these lions know how to hunt elephants. Anecdotal reports of elephant killings stretch back to the 1970s, but it's only in the last few decades that the latest generation of Savuti lions has garnered a reputation for its unique hunting abilities. Filmmaker Dereck Joubert recorded 74 elephant kills (including six adult females) by the famed pride between 1993 and 1996, and noticed that the lions showed a marked improvement in their pachyderm-killing skills year on year. Then, in 2006, a BBC crew filming with infrared cameras captured the cats in action:

Hunting elephants is risky business, and lions would probably stick to more manageable prey under normal circumstances. But with their typical quarry in short supply as a result of an annual migration, and a more-than-healthy elephant population still hanging around Savuti, the cats learned to expand their hunting repertoire.

According to reports, successful elephant hunts usually take place under the cover of darkness. The lions will strike when elephant herds number fewer than five, and the hunting group exceeds 27 cats. 

"The hunting that was witnessed was initiated by the lionesses that would storm at, and single out, an elephant of an appropriate size," explain researchers John Power and Shem Compion in an article on the Savuti lions. The first lioness to reach the elephant would launch itself onto the animal's back, sinking its claws into the thick-skinned hindquarters of its prey. "A second lioness would follow suit and also 'ride' the elephant's back, and while atop would persistently bite at the victim's spine. Two other lionesses were observed to hang onto either hind leg, and would also bite at the root of the tail if they could reach it. The other lions, including cubs, would run after the elephant. The elephants continued to run until they suddenly collapsed." 

Back in 2012, the Earth Touch film crew also managed to capture the Savuti pride's hunting prowess (the footage is pretty grisly, so viewer discretion is advised):