Why big cats kill their young: many reasons, not just accident?

A tigress killed her three newborn cubs in a zoo in West Bengal’s Siliguri last week while carrying them in her mouth. Her teeth damaged the windpipes of two cubs and the skull of the third. A zoo official described the deaths as “accidental”.

This was the second litter of Rika, the tigress, who had struggled with her first litter as well. In the same zoo, Rika’s sister Kika had lost both her cubs last year — one died soon after birth, and Kika abandoned the second, leading to severe malnutrition.

Infanticide in mythology…

Infanticide has been a recurrent theme in human history and mythology.

The ancient Spartans abandoned weak and deformed newborns at the Apothetae (place of rejection) on the slope of Mount Taygetus in southern Greece, the philosopher Plutarch wrote.

In Greek mythology, Cronus, the father of Zeus, devoured his newborns after it was prophesied that one of his children would dethrone him. (Zeus escaped because Rhea, Cronus’s consort, gave him a rock disguised as the infant Zeus, which Cronus swallowed.)

The myths of Oedipus and Perseus pivot on the abandonment of infants due to the perceived threats they posed to their father or grandfather.

…And among animals

It is not uncommon in animals either.

The male of the species is responsible for most infanticides in the wild. Upon taking over a rival’s territory and females, male cats kill the predecessor’s cubs, especially the males, to nip future competition and promote his bloodline.

Far less common are instances of filial infanticide in which the mother kills her cubs.

Resource management:

Like the Spartans, animals do not invest hard-earned resources in weak offspring. This is why mothers, both in the wild and in captivity, often reject or kill their cubs selectively to give the surviving ones a better chance.

* In September 2018, a lion cub born severely underweight in Kolkata’s Alipore Zoo was abandoned by her mother Sruti two days after the delivery.

* Earlier, in May 2013, leopard Basanti abandoned her cub after 32 days in a zoo in Jamshedpur. In Jhargram, also in Jharkhand, another zoo leopard, Harshini, fed her cub for six weeks before killing it in May 2020.

* In Gwalior Zoo, tigress Meena invested six months in her female cub who was born weak before killing it in September 2022. Her other cub, a healthy male, did well.

* In September 2023, Sumatran tigress Zayana killed her first cub after the second cub of the litter was stillborn in Auckland Zoo. In January 2024, she delivered a healthy litter of three, and raised the cubs well. Some experts believe the stillbirth overwhelmed Zayana; others think she wanted to invest in a bigger litter.

Hormones, inexperience

Conception and delivery trigger specific hormones to induce maternal behaviour. A hormonal imbalance, say experts, can lead to aggression in cats towards their cubs. First-time mothers and mothers who were orphaned in their infancy sometimes struggle to rear cubs.

* In August 2019, lioness Kigali, a first-time mother in Germany’s Leipzig Zoo, devoured her two cubs while grooming them.

* In August 2014, lioness Megha, also a first-time mother, picked up her cubs within hours of their birth in Indore Zoo, and all three died of neck injuries.

* Rupa, a white tigress in Odisha’s Nandankanan Zoo, stopped feeding her first litter in March 2022, leading to the death of two cubs. The third was hand-raised.

* In April 2014, an African lioness born in Pakistan’s Bahawalpur Zoo attended to her first litter of four cubs for a couple of days before refusing to feed them.

An inexperienced mother can be over-anxious while grooming or restraining her cubs. They often risk infection to their cubs by seemingly innocuous acts like licking the severed umbilical cords vigorously. But inexperience can lead to deadlier consequences as well.

* In May 2014, four newborn tiger cubs were killed under the weight of their mother Gauri in Ranchi’s Bhagwan Birsa Biological Park.

* In May 2019, a tigress in Dublin zoo rolled over her cub minutes after birth, killing it instantly.

* And in June 2012, white tigress Ganga killed one of her cubs by stepping on it in Bokaro Zoo.

Not all mothers get wiser with experience.

After delivering a cub in June 2022, tigress Lee in Maharashtra’s Gorewada Zoo groomed it by licking before lifting it by the tail to place it on dry grass. But while shifting it the second time, her canines dug into the cub’s neck. In February 2018, the same tigress had caused fatal neck and head injuries to her four cubs.

 Stress and insecurity:

Even cats that are well accustomed to captivity display an acute insecurity while with cubs, and are often overcome by a desperate protection instinct.

In June 2012, when the regular lion keeper at Hyderabad’s Nehru Zoological Park was absent, a substitute was sent to feed Rita, a 12-year-old lioness with two small cubs. Startled by the sight of a stranger, the lioness bit hard into one of her cubs, killing it.

In June 2013, after a zoo in Antwerp, Belgium, returned two lion cubs to their mother’s enclosure after vaccination, the lioness, Lorena, bit them to death. The zoo described Lorena as “a nervous lioness with a fiery temper” who had also killed one of her two cubs in 2011.

Easily misunderstood

In October 2018, Indianapolis Zoo staff watched as the lioness Zuri attacked and killed the lion Nyack, her companion of eight years and the father of her three cubs.

There are no explanations for Zuri’s violent aggression — which spotlights the limits to our understanding of animal behaviour in human terms. Their unsentimental resource management, say experts, are often misunderstood.

In the wild, a cat either eats her dead cubs to regain some of the energy she expended during pregnancy and feeding, or carries them away so the carrion does not invite predators to her surviving cubs. The same instincts are visible in captivity as well.