Even though we now know summer is about the tilt of the Earth rather than the brightness of Sirius (the dog star) as ancient Romans thought, the canine connection to the most sultry days of the season persists. We certainly share the misery of the hottest days.
Dogs have been keeping company with humans for at least 15,000 years, cats maybe half as long, but researchers continue to learn new lessons about our pets and how we influence each other.
One recent study, published in the journal Learning and Behavior, sought to test whether nurture or nature has more influence on the ability of a dog or wolf to beg effectively for food.
Researchers from the University of Florida found that wolves could be just as effective as domestic dogs at approaching attentive humans and taking cues from their hands, eyes and posture. And both wolves and pets got better with practice.
They also noted, though, that dogs that had been raised in a home environment rather than a shelter were better at picking up human cues. Those with less regular exposure to humans were less adept at begging.
In fact, dogs in close partnership with humans may actually become too sensitive and eager to please.
Scientists at the University of California at Davis found that drug or bomb-sniffing dogs were much more likely to give a false "alert" on a training course when their handler wrongly believed that a scent target was present.
They reported in the January issue of Animal Cognition that 18 human-dog teams erred more than 200 times over the course of an experiment.
The handlers had been falsely told that there could be up to three target scents in each of the rooms they searched, and that some would be identified with a piece of red paper taped to a cabinet.
The researchers said the mistakes didn't result from any failings in the canine noses or training, but because they picked up on cues from their humans about what they expected to find.
"Dogs are exceptionally keen at interpreting subtle clues, so handlers need to be cognizant of that to optimize the overall performance of the team," said Anna Oberbauer, senior author of the study and head of the university's department of animal science.
So what do dogs give back to us?
A March study by Michigan State University scientists found that people who owned and walked their dogs were 34 percent more likely to meet federal guidelines for physical activity. The researchers said the results appeared to come from more than just getting tugged tree-to-tree by Rover, but suggested that having a dog made people more active and perhaps healthy overall.
Another recent study by psychologists at Miami University and St. Louis University involved several surveys and other methods to identify the effect of pets on loneliness, self-esteem, frequent illness and exercise levels. They found that pet owners not only scored better in most measures, but that they also were more extroverted and enjoyed better social relationships with other people as well as with their pets.
Other researchers remain skeptical, though, complaining that most pet studies are not well controlled, rely too much on self-reporting by animal lovers and involve too few study subjects.
What dogs don't necessarily give us are germs or allergies.
Research done in 2009 by a veterinarian at Kansas State while working on her doctorate at the University of Tennessee found that dog owners who allowed their pooches to sleep on their bed or lick them in the face were no more likely to share E coli strains with the animals than those who did not. But there was a link between dog owners who didn't wash their hands after petting their dogs and then handled or cooking food.
A study published earlier this year by researchers at Henry Ford Hospital in Detroit showed that having a dog or cat in the house during the first year or so has little impact on whether a child will become sensitive to pet allergens by young adulthood, but that the exposure may be helpful in some groups.
Young men whose families had an indoor dog during their first year had about half the risk of being sensitized to dogs compared to those whose families had no house dog, the scientists wrote in the journal Clinical and Experimental Allergy.