Why Do Cats Kill Their Kittens?

All placental animals are hardwired to protect the lives of their offspring, to guarantee the next generation reaches adulthood. Mother cats (known as a queen) have a high maternal instinct and will nurture and raise her kittens until they have reached an age where they can safely care for themselves. But sometimes an adult cat will kill an individual or litter of kittens, which is termed infanticide. There are two types of infanticide, nonkin infanticide, which relates to the killing of unrelated young, and kin infanticide, which is the killing of related young (usually offspring).

There are a number of reasons an adult cat will kill a kitten or kittens, which vary depending on the gender of the cat.

Why do male cats kill kittens?

The most common reason a male cat will kill kittens is that they are not related to him. Male infanticide will trigger the female to come into heat (estrus). This allows him to pass on his genes to the next generation and remove unrelated kittens from the colony. Along a similar theme, if an intact male takes over a colony from another dominant tomcat, he may kill all unrelated kittens to establish his own line.

Not all male cats will kill unrelated kittens, some males have a strong paternal instinct towards kittens even if they are unrelated to them. One study found infanticide dropped in high-density cat colonies, possibly because a litter of kittens may have several fathers. [1]

Why do female cats kill their kittens?

Females killing their own kittens (maternal filicide) is thankfully a rare event but is more commonly seen than males killing kittens purely because the female is around kittens more than male cats. Infanticide may or may not involve consuming the kitten. Abnormal cannibalism is rare in female cats but can occur due to starvation, large litters, and second pregnancies. Normal cannibalism may also occur by accident when the queen severs the umbilical cord.

Maternal age:

The age of the mother also plays a role, with a higher incidence of neonatal infanticide in very young or geriatric mothers. Some female cats can experience their first estrus as young as 6 months and are not emotionally developed to care for a litter of kittens.

Maternal neglect:

In some cases, the death of a kitten may not be a deliberate action, but rather the result of maternal neglect. This may be attributed to young maternal age, sickness of the queen or stress.

Birth defects/disease:

Even if a kitten appears to be healthy to human caregivers, it may carry congenital defects or diseases invisible to humans. In this case, the mother cat may kill or abandon the kitten. This redirects her focus onto the healthy kittens, ensuring the survival of the fittest and potentially reducing the risk of an infectious disease spreading to the remaining littermates.

Accidental death:

The queen may unintentionally kill and accidentally consume a kitten immediately preceding birth if she chews the umbilical cord too close to the newborn kitten’s abdomen, or accidentally smothers the kitten. An unsupervised kitten death may be put down to infanticide when it was in fact not deliberate at all.

Ingrained hunting behaviour:

Cats are by nature predatory animals, and in rare cases, the queen’s hunting instinct is so strong that she mistakes her own offspring for prey.

Disturbed nest:

It is in the best interests of the queen to ensure she is expending energy only raising her own offspring. If the nest is disturbed, or the kittens are exposed to a novel scent. The queen may no longer recognise her kittens as her own and abandon or kill them.

How to reduce the risk of infanticide

Caregivers should take a hands-off approach when it comes to a queen and her kittens. Most queens have a strong maternal instinct and are capable of caring for their kittens without human help. During the neonatal period, the kittens mostly sleep and eat. Observe from a distance and only step in if the welfare of the mother or kittens is at risk. This is even more important with feral or stray cats, who have had limited human contact, or nervous cats.

Keep male cats away from nursing kittens, a slow introduction can wait until the kittens are weaning.

Place the nesting box in a quiet room away from the hustle and bustle of normal household activities. Place a litter tray, food and water a few feet away from the nest. Most queens will seek out a quiet and dark place before they deliver their kittens. This location may not always be practical, but where possible, accommodate the queen.

The socialisation window begins from weeks two to seven when the kittens should gradually be exposed to conditions they will encounter in day-to-day life such as interspecies (siblings) and intraspecies (humans, dogs) interactions and household sounds.

Will a female cat kill a kitten that is not theirs?

It depends on the environment the female cat is, as well as her nature. Some female cats are incredibly maternal and will willingly adopt an orphaned kitten. More likely, an unrelated female will reject an orphaned kitten rather than kill it, but infanticide is possible. Close supervision is critical when introducing an orphaned or abandoned kitten to a nursing female cat.

Should I leave an adult cat alone with a kitten?

A female cat who has had a litter of kittens and is attentive and loving towards her kittens can remain with her kittens until they have weaned. The caregiver should monitor both mother and her kittens, but do not intervene unless necessary. Provide plenty of high-calorie while the queen is lactating.

Generally, nonkin infanticide occurs when the kittens are neonate (under 4 weeks). Most kittens will remain with their mother until they are 8 – 10 weeks old. When a kitten is being introduced to a home with a resident adult cat, close supervision is critical in the first few weeks to ensure the adult cat doesn’t harm the kitten. Take time with introductions, to allow the adult cat to accept the new kitten. Keep the kitten away from the resident cat when there is nobody to supervise. A bathroom or laundry are ideal locations as they are easy to clean during toilet training.

Female cats who have previously killed a kitten or kittens in their litter should be removed from the breeding pool and spayed as there is an increased risk of maternal infanticide in further litters.

Resources:

[1] Coexistence between Humans and ‘Misunderstood’ Domestic Cats in the Anthropocene: Exploring Behavioural Plasticity as a Gatekeeper of Evolution – Eugenia Natoli, Carla Litchfield and Dominique Pontier