This Month in Dog Health: September 2022

Cover Image for This Month in Dog Health: September 2022
Brennen McKenzie, MA, MSc, VMD
by Brennen McKenzie, MA, MSc, VMD

1. Does your dog eat bugs? Insect-based dog food may be the future!

The most common protein sources in commercial dog foods are animals raised as part of the human food production industry, such as chicken, beef, and pork. More exotic ingredients, such as venison and kangaroo, are also available, though there is little research into the pros and cons of these newer protein sources. A few companies have begun incorporating an even more unusual protein source into their foods– insects.

Insects are a highly digestible source of protein, and can provide minerals and other important nutrients. They may also be less environmentally damaging to raise than conventional food species. So far, the limited research available suggests that insects could be a practical and healthy part of our canine companions’ diet, but more research is needed to truly understand the potential risks and benefits of this innovative food source.

Read more about this study here.

2. Pollution and cancer in dogs: Is there a connection?

Lymphoma is one the most common cancers in dogs, especially in certain breeds, like the Golden Retriever. While we know that some breeds are at greater risk than others, it is nearly impossible to predict whether any individual dog will get cancer because the cause is always a complex result of both genetic and environmental factors. The Morris Animal Foundation (MAF) is conducting one of the largest and longest-running studies of pet dogs in order to try and advance our understanding of how lymphoma and other cancers develop. 

The Golden Retriever Lifetime Study, begun in 2012, is following over 3,000 dogs to study a wide range of factors that determine health and aging. Loyal has partnered with MAF to contribute to this important work. Though the study is ongoing, some preliminary results are already being reported. 

A recent paper from MAF examined differences in the living environments of dogs that developed lymphoma and compared these with similar dogs that did not get this type of cancer. The goal was to identify any possible environmental factors  (things like secondhand smoke or living near sources of environmental pollution) that might increase the risk of lymphoma. 

Overall, the study did not find any specific environmental exposures that increased the chances of developing lymphoma. The study did, however, suggest that dogs living close to three or more sources of pollution might be more likely to develop one particular type of lymphoma. Further research will be needed to confirm this and identify any specific risk factors that dog owners might want to avoid. 

Read more about the study here.

3. Do sounds soothe sad dogs?

Many dogs experience stress or anxiety when separated from their owners, especially now that so many have been accustomed to constant human company during the pandemic. There has long been debate about whether music or other recorded sounds are calming to dogs and can reduce stress and improve welfare in a variety of situations. The evidence has been pretty sparse, and no firm conclusion is yet possible. 

A recent study has added a bit of data to the mix. The researchers briefly separated dogs from their owners in a laboratory setting and exposed the dogs to either classical music or a Harry Potter audiobook. There were some minor differences in how long the dogs took to lie down and how much attention they paid to the speaker when the sound was playing, but overall neither sound seemed to have much impact on the dogs’ behavior. 

More research is needed to identify what behavioral benefits, if any, different kinds of sounds may have for dogs. Until we have a clearer picture, we shouldn’t assume our dogs really enjoy listening to the radio or curling up with an audiobook.

4. Tears of joy: dogs tear up when they see their owners

Have you ever cried tears of joy? This is usually thought to be a uniquely human response to strong emotions, and it is thought to be related to the importance of social bonds in our species. We need others to know how we feel in order to survive together as a tight-knit group. A new study, however, suggests that our dogs share this unusual behavior.

Researchers measured tear production in dogs right after a reunion with their owner and also after a greeting from an unfamiliar human. The dogs didn’t exactly weep, but they did produce more tear fluid when reuniting with their owners than when meeting strangers.

This may be due in part to the domestic dogs’ need for a close bond with the humans they depend on. In the same study, people were shown pictures of dogs with normal amounts of tear fluid and dogs with a little extra tearing (caused by adding artificial tear drops, just like actors sometimes do when they need to cry in movies). Humans felt more positively about dogs who were “tearing up” a little, suggesting dogs might have developed this rare behavior to help them bond with us and get more human care.

5. The canine-human bond: is it just for dogs?

There is no doubt that dogs and humans have a special connection. Scientists have long wondered if the wolf ancestors of today’s domestic dogs were domesticated partly because they could share this connection, or if dogs had to be domesticated first, before they could bond with people. A recent study suggests wolves hand-raised by humans can form attachments to individuals, so that ability was already present before we started domesticating them. 

However, even hand-raised wolf pups have a much weaker connection to humans. They don’t play with us like puppies do, and while they are comforted by the presence of a person they know, they are afraid of unfamiliar humans, while puppies seem to start out ready to love everybody. Wolves and dogs share a lot of characteristics, but thousands of years of interaction with humans have made dogs uniquely suited to being our species’ best friends.

Read more about the study here.


  1. Valdés F, Villanueva V, Durán E, Campos F, Avendaño C, Sánchez M, Domingoz-Araujo C, Valenzuela C. Insects as Feed for Companion and Exotic Pets: A Current Trend. Animals. 2022; 12(11):1450.
  2. Luethcke KR, Trepanier LA, Tindle AN, et al. Environmental exposures and lymphoma risk: a nested case–control study using the Golden Retriever Lifetime Study cohort.Canine Med Genet 9, 10 (2022).
  3. Kinnaird RF, Wells DL. The effect of auditory stimulation on pet dogs’ reactions to owner separation. Appl Anim Behav Sci. 2022; Vol. 254;105688.
  4. Murata K, Nagasawa M, Onaka T, Kanemaki N, Nakamura S, Tsubota K, Mogi K, Kikusui T. Increase of tear volume in dogs after reunion with owners is mediated by oxytocin. Curr Biol. 2022 Aug 22;32(16):R869-R870. 
  5. Wheat CH, Larsson L, Berner P, Temrin H. Human-directed attachment behavior in wolves suggests standing ancestral variation for human–dog attachment bonds. Ecol Evol. 2022;12(9):e9299.
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