Study: Orphaned kittens show more stress

Orphaned kittens experience more stress than those who are cared for by their mothers, according to a new study from the University of California, Davis (UC Davis).

And it shows.

Many young animals cry in distress when socially isolated, and these cries may help their mother find and retrieve them. Likewise, increased physical activity may help young animals find their way back to their nests.

In the study, the researchers assessed the effects of early maternal separation on the vocalizations and physical activity of 49 kittens (28 orphaned,* 21 mother-reared; 23 female, 26 male) from 11 litters (5 mother-reared, 6 orphaned). Each kitten was placed alone in a pen away from the rest of the litter and/or mother for two minutes at the age of one week, and again at three weeks. The researchers recorded the number of vocalizations and total physical activity for each kitten.

The orphaned kittens showed increased physical activity and distress calls compared to mother-reared kittens both times, suggesting that maternal separation may lead to long-term changes in stress responses.

Thousands of kittens are orphaned each year, whether through neglect, the death of their mothers, or accidental separation from their mothers. Orphaned kittens often end up in animal shelters or foster homes. The researchers say that understanding the effects of being orphaned on stress responses could improve their care.

NEWStat contacted lead author Mikel Delgado, PhD, a postdoctoral researcher on cat behavior at the UC Davis School of Veterinary Medicine, to find out more.

NEWStat: What spurred you to do this study?

Mikel Delgado: We have been studying the health and behavior of orphaned kittens for a few years now. We’re working with these kittens in part to see whether their experiences have any parallels with adverse early life experiences in other animals, including humans. We know that these adverse experiences can impact the later health and behavior of other animals.

We also know that [neonatal] kittens spend a lot of time in contact with their mothers. In other species, that early physical contact with mom is important for the regulation of pain, sleep, and stress responses.

NEWStat: Orphaned kittens may end up being hand-raised by humans in shelters or foster homes. In those cases, are there any benefits to the kittens?

MD: We have no empirical studies to tell us for certain what any benefits might be. But, as an example, orphans are hand-fed and do not have to compete for a nipple; they can feed on as much formula as they like without competition. They also may get additional handling by humans while they are in their sensitive period for socialization; this may help them be more ready to bond with humans when they get adopted.

NEWStat: What do you hope will be the major takeaways of this study for NEWStat readers?

MD: Until we know more about the effects of being orphaned on kittens, we should do everything we can to provide them with a similar environment to that they would experience with mom, such as making sure they are provided with a source of warmth and comfort, gentle handling, and the social company of other kittens. Hopefully, this will give them the best opportunity to cope with an adverse early life experience. Ideally, orphans can get placed with another mother cat, but rescues often don't have available moms who can act as a surrogate.

NEWStat: Where do you go from here in terms of research on orphaned kittens?

MD: We [want] to know whether these stress responses continue into later kittenhood or even into adulthood. We’re currently looking at how orphans and mother-reared kittens differ in health and behavior during the process of weaning from milk or formula to solid food. Hopefully, in the future, we can do studies that follow kittens into their new homes until they are adults!

*All of the kittens and mother cats were cared for in foster homes; no kittens were deliberately orphaned during the course of this study.

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