While dogs cannot comprehend pregnancy in the complex way that humans can, there is evidence to suggest pregnant dogs exhibit behavioral changes indicating they have some sense of their pregnant state. Dogs go through dramatic physical transformations during pregnancy and experience hormonal fluctuations that may alter their disposition. Additionally, their powerful sense of smell likely allows them to detect physiological changes. Though the full extent of dogs’ understanding of pregnancy remains unknown, observable behavioral shifts, especially in late term pregnancy, suggest some rudimentary awareness on their part.
Physical Signs
One of the most obvious signs of pregnancy in dogs is an enlarged abdomen. As the puppies grow in the uterus, the mother’s belly will expand and appear rounded underneath. According to the Michigan Animal Hospital, a dog’s abdomen may grow up to 1.5 times larger than normal during pregnancy.
Along with abdominal enlargement, pregnant dogs will also experience weight gain. The extra weight is necessary to support the developing puppies. Per Noah’s Ark Veterinary Clinic, weight gain becomes especially noticeable in the last three weeks of pregnancy when the puppies grow rapidly. Dogs typically gain 15-25% of their body weight while pregnant.
Additionally, a pregnant dog’s nipples will enlarge and redden in preparation for producing milk. The nipples start to protrude outward and increase in size around 1 month into pregnancy. PetMD notes enlarged nipples are often one of the earliest physical indicators of pregnancy.
Other physical signs to look for are lethargy, vomiting, and changes in appetite as the dog experiences nausea and fatigue from hormonal fluctuations early on. Physical changes become most prominent in the last trimester when the fetuses grow substantially.https://www.michigananimalhospital.com/site/blog/2021/11/30/dog-pregnant-signs
Behavioral Changes
As their hormones fluctuate during pregnancy, dogs often exhibit behavioral changes. Some of the most common changes are:
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Nesting – Pregnant dogs may collect items like toys, clothes, or blankets and arrange them into a nest. This maternal instinct prepares them for the arrival of puppies. As delivery nears, nesting behaviors increase. (Source)
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Mothering Toys – Pregnant dogs may carry around or mother stuffed toys. This also taps into their maternal instincts. (Source)
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Lethargy – Fatigue and increased napping are common as pregnancy progresses and the puppies grow. The dog is expending energy on the pregnancy. (Source)
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Appetite Changes – Appetite often fluctuates during pregnancy. Some dogs eat less in the first weeks due to morning sickness. But most have increased appetite later on to nourish the puppies. (Source)
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Protective/Aggressive Behavior – Pregnant dogs can become more protective and aggressive. Their maternal instincts lead them to guard their den and puppies. Owners should supervise interactions with children or other pets. (Source)
Sense of Smell
Dogs have an incredibly acute sense of smell that is 10,000 to 100,000 times more sensitive than humans’. Their olfactory ability is linked to 300 million olfactory receptors in their noses, compared to about 6 million in people.
According to Can dogs sense pregnancy? Signs your dog knows you’re …, dogs can detect tiny changes in hormones, specifically estrogen and progesterone. These hormones fluctuations can notify dogs of ovulation or pregnancy before symptoms are outwardly apparent. Dogs are essentially able to smell the hormonal production of hCG, human chorionic gonadotropin, the indicator of pregnancy.
With their advanced olfactory senses, dogs can pick up on these subtle hormonal shifts, alerting them to their owner’s pregnancy status. Their early detection is possible because of their incredible sense of smell.
Instinctual Knowledge
Female dogs have strong maternal instincts that drive their motherly behaviors, even if it’s their first pregnancy. According to the AKC, mother dogs know how to care for their puppies as soon as they give birth. 1 This is due to hormonal changes during pregnancy and labor that activate their maternal caretaking abilities.
Specifically, levels of oxytocin and prolactin surge during birth and nursing. Oxytocin facilitates bonding between a mother and her pups, while prolactin supports milk production. 2 These hormones essentially “flip a switch” that turns on a dog’s maternal instincts.
Additionally, female dogs likely have an innate awareness of their pregnant state. According to PetHelpful, expectant mother dogs become more affectionate, nesting, and protective of their territory – behaviors aimed at preparing for puppies. 3 Even without conscious knowledge, their bodies inform them of the puppies to come.
Much Still Unknown
The full extent of dogs’ self-awareness of pregnancy is not well understood by science. While dogs do exhibit some behavioral changes when their owners are pregnant, researchers have not conclusively proven whether dogs have an innate understanding that they are expecting puppies.
As stated in a USA Today article, “Experts aren’t in agreement as to whether dogs actually understand what it means to be pregnant.” [1] Much of their changed behavior may simply be in response to changes in routine, diet, and their owner’s hormone levels.
Although many dog owners believe their pets knew they were pregnant before even they did, controlled scientific studies are still needed. Since dogs cannot speak human languages, it remains challenging for researchers to definitively conclude what dogs comprehend. As concluded by The Bump, “While some researchers agree dogs most likely can sense pregnancy, others assert there isn’t enough scientific evidence.” [2]
Owner Influence
While dogs lack the ability to innately understand pregnancy in the way that humans do, dog owners and veterinarians can help communicate information about the pregnancy to the dog. For example, owners can use the dog’s sense of smell and associate rewards with the dog’s changing body as the pregnancy progresses. According to The Kennel Club, the vet may be able to palpate the dog’s abdomen starting around 3-5 weeks into the pregnancy to feel for embryonic swellings1. As the dog enters the final weeks of pregnancy, the owner can limit exercise and stimulate milk production to prepare the dog for whelping.
The actions of the owner before and during the pregnancy play a major role in supporting the dog through this process. While the dog may not fully understand the pregnancy, clear communication and extra care from the owner can help create a safe, comfortable environment for the expecting mother.
Individual Factors
A dog’s individual experience and breed can influence their awareness and symptoms during pregnancy. According to a study published in Theriogenology, the duration of pregnancy can vary between breeds, with smaller dogs tending to have shorter gestations and larger dogs having longer ones (Okkens, 2001).
For example, a Chihuahua’s pregnancy may last only 56 days while a Great Dane’s can last up to 72 days. This means larger breed dogs like Great Danes may show signs and have awareness earlier. Smaller breeds with shorter gestations like Chihuahuas may not exhibit noticeable changes until later (Belly Labs, 2023).
A female dog’s experience with previous pregnancies can also impact their awareness. Dogs who have been pregnant before may recognize symptoms and changes earlier than first-time mothers.
Late Term Changes
As a dog’s pregnancy progresses to the final weeks before delivery, some of the most profound behavioral changes will occur once the signs of pregnancy become obvious.
According to https://www.healthline.com/health/pregnancy/can-dogs-sense-pregnancy, in the last 2-3 weeks of pregnancy, a dog’s appetite may decrease as the dog’s abdomen enlarges. They also tend to want more affection and become more attached to their owners as their due date approaches.
https://www.southseattlevet.com/5-signs-your-dog-is-pregnant states that as a pregnant dog enters the final week before labor, her temperature will drop below 100°F, signaling that labor is imminent within the next 24 hours. The dog’s mammary glands will enlarge, sometimes leaking milk, and she will start nesting – seeking secluded places to give birth.
Overall, the most noticeable late term changes are the dog seeking more affection, showing nesting behavior, and having an enlarged abdomen and mammary glands as signs of pregnancy become unmistakable.
Conclusion
When considering all the behavioral, physical, and instinctual changes that occur during a dog’s pregnancy, it appears that dogs do have some basic awareness that “something” is happening with their bodies. The swelling abdomen, milk production, nesting behaviors, and protectiveness all point to dogs having a rudimentary understanding of their pregnant condition.
However, it’s unlikely that dogs have the same complex thoughts and anticipation of motherhood that humans do. Dogs operate primarily on instinct, smell, and environmental cues. While they may sense the physiological changes in their bodies, their comprehension is limited compared to humans.
The full extent of a dog’s awareness remains largely unknown. More research is needed to determine how much dogs may intuitively understand about pregnancy and the coming responsibilities of motherhood. But in general, while dogs experience many tangible changes and natural instincts, their cognitive understanding about being pregnant appears basic compared to that of people.
