According to the American Society for the Prevention of Cruelty to Animals (ASPCA), around 6.3 million companion animals enter animal shelters in the US every year—roughly 3.1 million dogs and 3.2 million cats. With numbers this high, it’s no surprise that quite a few shelters might be overwhelmed by the workload.

To make matters worse, parallel to the abundant numbers of animals, shelters have to deal with a shortage of helping hands. Lack of human resources, including foster support, as well as staffing and volunteer support are among the main problems impacting nearly 90% of animal well-fare organizations, Animal Welfare Advancement reports.

Fortunately, there are some people who take matters into their own hands and help improve the situation in shelters one adopted critter at a time. ASPCA points out that roughly 4.1 million animals are adopted annually—2 million dogs and 2.1 million cats.

No matter the pet one adopts, life with the critter tends to become quite an adventure. But the oftentimes goofy additions to the family might need time to relax or show their true character upon arriving at their new forever home.

In order to know what to expect after adopting a pet—a cat, in this case—and to learn what determines their behavior, Bored Panda discussed the subtleties of living with a feline with Jonathan Losos, a professor of biology and the author of The Cat’s Meow: How Cats Evolved from the Savanna to Your Sofa.

One of the main points the expert addressed was the fact that many people are under the impression that cats are aloof loners; but it’s not always the case. “As a result, they think that having a single cat is ok and don’t worry about leaving the cat alone for long periods of time,” he suggested.

“Some cats are ok with that, but many are not—they enjoy interaction with people and, in some cases, with other cats. Often, it is better to adopt two cats simultaneously, particularly when they are littermates.”

According to Prof. Losos, the need for companionship is a quirk of cat biology, which relates to their predecessor wild cat. “Lions are the only truly social species of wild feline. Everyone is familiar with prides of lions, in which pride members are very friendly to each other, grooming and playing together and lying on top of each other. Females will even nurse each other’s cubs.

“The basis of lion pride sociality is that the females are all related to each other because females tend to remain in the pride, whereas males leave when they approach maturity. The result is that female pride members are mothers-and-daughter, sisters, cousins, and so on.”

“It turns out that in some circumstances, domestic cats form very similar social groups. This occurs when there are a lot of cats living in the same place,” the expert explained, pointing out why adopting cats from the same litter might be a good idea. “Like lions, members of a group are very friendly to each other, even sometimes serving as midwives during birth. And, again like lions, group members are related because the females remain with the group, but males leave. Multiple groups can occur in the same place, and group members are not at all friendly to members of other groups.

“As a result, domestic cats have a rule-of-thumb: if I’ve lived with a cat my entire life (or the other cat’s entire life if it is younger), then be friendly, but if I don’t know this cat, then be much more wary. And that’s why, if you’re going to have multiple cats in your household, you’re going to have better success if you adopt littermates. 

“That doesn’t mean that bringing unrelated cats into a house can’t work out, but the outcome is much less predictable: sometimes they become good friends, sometimes not,” Losos added.

“Another issue with adopting a cat is not realizing that cats are extremely intelligent, curious beings. They need mental stimulation. New toys, new smells, new objects to explore,” Prof. Losos told Bored Panda.

“They like to climb, both because of their curiosity and because they feel safer from a high vantage point. The reason for that is that in the wild, their ancestor, the African wildcat, is not only a consummate predator, but also potential prey to larger predators like leopards and hyenas. Getting off the ground is a way of being safe, and this urge remains in our household pets (probably reinforced when living with dogs or little children).”

These feline characteristics might require the new owners to make certain adjustments around the house or buy an additional item or two (a tall scratching post, for instance). But let’s be honest—it’s likely to end up being more than two as anyone with a pet knows how dangerous a game buying toys for their critter can be.

It’s fairly clear that cats tend to have quirks the owner has to get used to, but their quirky, often unpredictable behavior is one of the main reasons people enjoy being around them. Professor Patricia Pendry of Washington State University pointed out that sometimes the feline’s behavior might even make the owner feel special.

“The subtle and somewhat unpredictable responses cats give us, give us the perception that we are chosen—or perceived as ‘special’ when a response from a cat does occur,” she told Medical News Today. She added that because the response from a cat might take some time to emerge, people tend to be very curious about what it will do, which might result in them giving the critter their undivided attention.

Taking everything into consideration, one thing is clear—life is never boring with a cat (as with most pets, likely). That might be one of the reasons people make the decision to adopt them, but no matter the reason—and no matter the pet, for that matter—we’re happy they do, hence this list of appreciation. For earlier editions of adopted critters in their forever homes, continue to browse last month’s list or feel free to go as far back as August.