Curiosity

 

When do puppies develop their sense of smell? Today is Surprising Saturday, and we thought it was quite surprising learning that puppies are capable of using their sense of smell even before they are born! What’s even more interesting though is that there seems to be an evolutionary advantage as to why a pup’s sense of smell is present so soon. And this isn’t exclusive to puppies, it’s something that apparently occurs in human infants too. Read on to learn more.

The Aniseed Study

In a study conducted by Peter G. Hepper and Deborah L. Wells and published on Oxford Journal, 16 pregnant dogs were divided into four groups composed by four dogs. The first four pregnant dogs were fed a diet flavored with aniseed, a spice known for its aromatic scent and for being safe to use in dogs. The pregnant dogs were fed this diet during the last 20 days of gestation. The second group of four dogs were fed the aniseed flavored food the day after giving birth for the duration of 20 days. The puppies were expected to be indirectly exposed to the aniseed scent/flavor when suckling for the first 3-4 weeks. The third group of pregnant dogs were fed the aniseed flavored food both before the birth of their puppies and afterward. Finally, the fourth group of pregnant dogs were fed a normal diet with no aniseed flavor added.

[otw_is sidebar=otw-sidebar-1]

The Intriguing Results

During the study, the puppies stayed in their owner’s home and none of them were exposed to aniseed other than indirectly from the mother’s diet. All puppies were weaned from milk to solid food at around 4 to 5 weeks of age, and at 10 weeks, when the puppies were tested, all of them were eating solid food. In the test, the puppies were tested by offering them a choice between some minced chicken with a drop of aniseed and some minced chicken with distilled water. These foods were offered over the course of several days. The strongest preference for the aniseed flavored chicken was observed in the puppies who were exposed to aniseed both prenatally (in the womb through amniotic fluids) and postnatally (from the mother’s milk). Little interest for the aniseed flavored chicken was shown in both the puppies exposed to aniseed exclusively when in the womb or exclusively when nursing.

Practicing Breathing Muscles

Further proof of puppies using their sense of smell when still in the womb comes from taking a peek at them via ultrasound. Through an ultrasound, scientists were capable of gaining an “inner view” of what goes on in the womb two weeks prior to the puppies being born. The scientists found that the puppies were “exercising” their breathing muscles during this time. It’s likely that this “breathing time” provides puppies the opportunity to learn more about their mother’s distinct odor and the odor of the food she has been eating, suggests animal behaviorist John Bradshaw in the book “Dog Sense: How the New Science of Dog Behavior Can Make You A Better Friend.”

An Evolutionary Role

Why would puppies rely on their sense of smell when they are still in the womb? Interestingly, there may be an evolutionary advantage. This form of chemosensory prenatal learning may aid the puppy in learning what foods are safe to eat when weaning time is around the corner. With smells passing through the amniotic fluid, and then flavors passing in the milk, puppies may rely on their mother’s knowledge to learn about which foods are safe to eat and this can influence the puppy’s future dietary preferences. These two types of prenatal and postnatal exposure, provide the puppies with a longer period of experience on what’s safe to eat, important factors that aid in promoting their survival, further explain Peter G. Hepper and Deborah L. Wells in the study.

References:

Perinatal Olfactory Learning in the Domestic Dog, Peter G. Hepper, Deborah L. Wells, Oxford Journal, Chem. Senses (March 2006) 31(3): 207-212.

[otw_is sidebar=otw-sidebar-1]

 

It’s Talent Thursday, and today we would like to discover some more details about dogs who are putting their sniffers to work for a noble cause: detecting illnesses, in particular cancer. How do dogs detect cancer? Does cancer have a specific smell that dogs can discriminate from other smells? We have found some interesting findings on the subject, so we’ll be sharing them this Thursday in honor of our dog’s talented sniffers. So let’s take a look at our dog’s powerful sniffers, how they can help in detecting cancer and the type of training cancer-detecting dogs must go through.

A Powerful Sniffer

In order for dogs to detect cancer, several conditions must be met: the dog must have a sense of smell that is powerful enough to detect its smell, the cancer must release a distinctive smell that makes it stick out from other smells and the dog must be properly trained to let us become aware of it. When it comes to having a powerful sense of smell, there’s no doubt that dogs have powerful sniffers. While humans have only a mere 5 million olfactory receptors, it’s estimated that dogs have an outstanding 300 million. On top of that, the part of the dog’s brain responsible for analyzing odors is 40 times greater than ours. In the book “Inside of a Dog, What Dogs See, Smell, and Know,” Alexandra Horowitz, a cognitive scientist and researcher at Barnard College, offers a good example of how powerful those sniffers really are. While we are barely capable of noticing that our coffee has a teaspoon of sugar added to it, a dog is capable of detecting one teaspoon of sugar in a million gallons of water. That’s about the size of two Olympic-sized pools!

[otw_is sidebar=otw-sidebar-1]

Does Cancer Have a Smell?

So dogs have a powerful sense of smell, there’s no bones about that, but does cancer emanate a distinctive smell? This is not an easy question to answer since our poor sense of smell may not be powerful enough to detect such smells especially at its earliest stages. Sure, there are nurses and oncologists who claim to have smelled cancer in their patient’s breath, but this appears ot occur mostly in the most advanced stages. While there is some anecdotal evidence coming from dog owners claiming that their dogs showed a strong interest towards a specific spot or area on their skin that was later found to be cancer, the good news is that more and more promising, and most of all, “palpable” evidence is coming through.

Interesting details come from one of the latest studies published in the Journal of Urology. In this study, two female German shepherds trained for Explosion Detection were trained to identify specific volatile compounds in the urine samples of patients suffering from prostate cancer. The dogs were then tested on 362 patients suffering from prostate cancer and 540 healthy individuals that did not have cancer. Of course, further studies will be needed to further prove any potential predictive values for future use of dogs for this purpose, but overall the results were quite remarkable with both dogs showing promising abilities in detecting compounds associated with prostate cancer.

An Instinctive Behavior

When it comes to putting their powerful sniffers to work, dogs may retain an instinctive tendency to become interested in smells that suggest disease. This tendency may date back to the days when canines had to mostly fend for themselves. Predators by nature are attracted to prey animals that are sick or injured in some way, explains the InSitu Foundation, an organization that has been dedicated to scientifically training dogs to detect early stage cancer in humans for over 12 years. Sick, slow and injured animals are the most vulnerable and the easiest to be caught. After many years of hunting, predator animals learn to associate that “sick scent” with an easy meal so they’re naturally drawn to it. Even when dogs didn’t specifically hunt, but were acting more as scavengers, they were (and continue to be) attracted to the smell of sickness, disease or something rotting as this played a big role in their survival.

Perfecting the Training

Just because dogs are naturally drawn to certain smells, doesn’t mean that they are born knowing what to do when it comes to detecting specific odors. Dogs require extensive training in order to learn to detect and alert about the presence of compounds suggestive of cancer.

According to the InSitu Foundation the process is similar to training dogs to detect bombs and narcotics. The odor is simply paired with a high value reward, in a similar fashion as predators learn to pair the smell of a sick prey with an upcoming meal. Through repeated pairings, the conditioning process teaches dogs to become highly motivated to seek out that smell.  However, it’s not that easy. If breath is being analyzed, the specific compound must be isolated as the dog needs to learn how to discriminate it from other smells in breath. This would require exposure to many samples so that the dog can be taught exactly what to look for. Finally, the dog must alert of its findings. Dogs may stop and sit down by the sample or they may lick the bottle to communicate that they have positively detected the scent of cancer cells. So things look promising so far in the cancer detecting department. According to UC Davis Health System, researchers have established that dogs are so far capable of recognizing melanoma as well as bladder, lung, breast and ovarian cancers. We shouldn’t therefore be surprised if one day we’ll see furry coats along with lab coats in future cancer diagnostic settings.

References:

Alexandra Horowitz, “Inside of a Dog, What Dogs See, Smell, and Know,” Scribner; September 28, 2010

Olfactory System of Highly Trained Dogs Detects Prostate Cancer in Urine Samples, The Journal of Urology, April 2015 Volume 193, Issue 4, Pages 1382–1387

[otw_is sidebar=otw-sidebar-1]

 

For those folks looking for good running partners, what’s better than a dog? Other than some teeny lap dogs, short-faced dogs who have trouble breathing and overheat, and a few couch potato breeds that would rather snooze than go for an outdoor romp, many dogs make suitable running partners who would say “woof!” without hesitation if they were asked to go for a nice jog with their favorite humans. Sure, dogs have energy, they like to spend times outdoors and they’re willing to accompany their owners just about anywhere as long as it’s a fun place to be, but what really makes dogs good running partners? Let’s delve deeper into what makes dogs particularly adept to making great running partners.

Dogs are Cursorial Animals

Let’s face it, some animals appear to have been purposely crafted for running. A cursorial animal simply means that its body has specifically adapted for the purpose of running. Running for what though? It depends. Cursorial grazers such as horses relied on running to escape predators and to cover lots of ground in search of optimal pastures; whereas cursorial predators such as wolves relied on running for chasing and catching prey. Examples of cursorial animals therefore include dogs, cats, horses and gazelles. What do these animals have in common? They have developed longer legs and their bodies have undergone adaptations to allow them to effectively run under the form of longer legs, modified feet and the development of hooves, according to the Museum of Osteology.

[otw_is sidebar=otw-sidebar-1]

Dogs are Digitigrade Animals

While humans are plantigrades who walk on the soles of their feet, dogs are digitigrades, which means that they walk on their toes. We often think of a dog’s paws as their hands and feet, when in reality we are mainly looking at their toes as seen in these illustrations.  The bones that correspond to our wrists and ankles are set much higher than we would think which explains why many people often confuse the dog’s ankles (hocks) for the dog’s knees (stifle). This explains why many artists have difficulty in drawing animals and develop “backward knee syndrome,” explains Kim B. in a blog for artists.

One big perk of being digitigrade is that walking on the toes allows them to move around more quietly and attain faster speeds, explains Theresa A Fuess, a veterinarian working for ‎Veterinarian at Lakehills Animal Health. Other animals classified as digitigrades include wolves, coyotes, bobcats and foxes, adds Mary Hoff, a freelance science writer in an article for the Minnesota Department of Natural Resources.

A Word of Caution

Sure, many dogs have the potential to make wonderful running partners, but it’s always best to practice caution to prevent potential injuries to our four-legged friends. A good place to start is by looking at the dog’s age. Many people get a puppy and can’t wait to start jogging with him, but it’s best to consult with a vet first as to when to take the pup along. Just as in children, a puppy’s skeletal system is developing, and starting an inappropriate exercise regimen too soon can cause potential damage to the puppy’s growth plates. Growth plates are soft areas of developing cartilage tissue that are found at the ends of the puppy’s long bones. If too much exercise or the wrong type is implemented before the growth plates harden and close, they are vulnerable to being injured and potentially fractured. An injury to the puppy’s leg during this time may result in lots of damage and potential deformity, warns veterinarian Karen Becker. Consider that for large breeds skeletal maturity is reached at a later age (generally 18 months to 2 years) compared to smaller dogs, cautions veterinarian Chris Zink, a canine sports medicine and rehabilitation specialist. Consult with your vet for specific recommendations.

Another issue, when choosing dogs as running partners is failing to properly condition them to an exercise regimen. Just as in human athletes, slow and steady is the way to go. Sure it doesn’t take dogs too long for them to attain a good conditioning level as their physiology is designed for endurance, but starting slowly and gradually helps lay out the groundwork and ups the chances for success, suggests, Robert Gillette, veterinarian and director of Auburn University’s Veterinary Sports Medicine Program. Again, best to consult with a vet for the best exercise program for your dog.

[otw_is sidebar=otw-sidebar-1]

 

Puppy accidents: no matter what your breeder and that promising book you have purchased have told you, they will occur in your home sooner than later. Potty training puppies as with potty training children, takes patience and time, so unless you won a stuffed puppy at some carnival game, those bladder and bowels will empty no matter how assiduously you stick to a puppy potty training program. As with many things in life, if it sounds too good to be true, it likely isn’t true at all, and new puppy owners often learn this the hard (and often frustrating) way.

Housebroken Puppies Ready for New Homes!

Yes, it’s true that many breeders implement some preliminary potty training basics when the puppies are in their care, but don’t expect to have all the homework done when your puppy comes home. Puppies have a hard time generalizing what they have learned in the breeder’s home. Just because a puppy was housetrained in the breeder’s place doesn’t necessarily mean he’ll be able to transfer the skill into a totally new context without help, explains Nicholas Dodman, in the book Puppy’s First Steps. It would be more realistic if certain breeders would explain that their puppies were introduced to potty training and that the new puppy owners must continue the training from day one, and that yes,they should expect some accidents along the way!

Potty Train Your Puppy in Under One Week!

Also, misleading is a new trend of books, e-books and videos making promising statements such as “How to potty-train a puppy under 7 days.” Sure, this is an effective sales pitch, who wouldn’t dream of a puppy who learned how to potty outside in just under a week? So new puppy owners purchase the book, try to adhere to the program and then get upset when they notice it isn’t working its magic. We can almost hear them say something in the terms of “What? It’s day 8 and the puppy had an accident?” Turns out, titles like these will only lead to frustration.

Use this Formula for Success!

Another common misleading statement that can lead to problems is suggesting the “puppy month’s plus one rule.” This is something we hear trainers often repeat “ad nauseam” to their clients. The rule dictates the frequency a puppy should be taken out by calculating the puppy’s age in months and then adding one. So if say the puppy was 3 months, you would add 1 and therefore the puppy should be taken out every four hours. This leads to frustrated puppy owners when they discover that their puppies are unable to make it for the whole four hours. Unfortunately, potty training is not math, and equations as such will not work thier magic. For instance, if the puppy had some rough play time, he’ll likely guzzle down a lot of water, and then in an hour or two, the Niagara falls will open, leading to “unexpected messes.” Also, young pups need to be taken out after they wake up from a nap or after playing. Last time we checked, puppy bladders didn’t have a counter, so it’s not like the puppy’s bladder is counting down the minutes with the predictability of a kitchen timer.

[otw_is sidebar=otw-sidebar-1]

Aunt Mary’s Training Was Easy as Pie!

Last but not least, be wary of aunt Mary who says her puppy was so smart she was potty trained in under 10 days. She may not truly recall how long it really took (things from the past often seem far easier than they really were) or she may have missed some piddles. It’s not uncommon to hear some people say “Oh, our Betsy was potty trained in what, 2 weeks?” and then the daughter remarks: ” but mommy, did you forget all those accidents we found later when we moved the couch?” It’s quite easy to miss little sprinkles from pint-sized dogs like Chihuahuas and toy breeds, versus the Lake Michigan-like puddles of a mastiff or great dane!

The Physiology Behind Puppy Accidents

Potty training puppies is not something that will happen overnight. Puppy owners need to be patient, understanding  and learn effective methods to help their puppies succeed. Understanding better the physiology behind puppy accidents, can help new puppy owners understand why it’s so unrealistic to expect puppies to be potty trained in under a week and why certain mathematical formulas should be restricted to fixed variables that are constant versus things that are unpredictable and so variable such as puppy bladders and bowels!

No Sphincter Control

In dogs, and any living being equipped with a bladder, urine is constantly accumulating. At a certain point, when the bladder is full and reaches its threshold, special stretch receptors in the bladder wall activate. This triggers the contraction of muscles of the bladder wall (detrusor muscles) which give the dog the sensation of having to urinate. When dogs acknowledge this sensation, they may go to the door and bark to ask their owners to be let out. Control of the muscular sphincter found around the neck of the bladder allows them to hold the urine. Then, once out, they can can relax the sphincter and urinate.

In young puppies, when the bladder wall contractions take place, they are unable to control their muscles of their sphincter so emptying of the bladder occurs at this point. So the moment they realize they need to go, their bladders are already emptying. At what age do puppies attain sufficient muscle tone to allow them to control things a bit more? Stanley Coren, in his book “Born to Bark: My Adventures with an Irrepressible and Unforgettable Dog” claims that full control isn’t reached until the puppy is 5 to 6 months. So let’s do some real math here. If most puppies are 8 weeks when they go to their new homes, how can they be already house trained? And how can they be possibly be house trained in under one week?

The Gastrocolic Reflex

One main reason why the month plus one rule is faulty is the way a pup’s gastrocolic reflex works. Right after a meal, a dog’s gastrocolic reflex will increase the motility of the colon. This causes the rectum to fill up which stimulates the smooth muscle of the internal anal sphincter and the striated muscle of the external anal sphincter, explains  Katherine A. Houpt in the book “Domestic Animal Behavior for Veterinarians and Animal Scientists.”

 This means  that shortly after eating, most puppies will have a need to defecate, which can set a puppy (whose owner adheres to the puppy moth plus one rule) to failure. You can almost hear frustrated new puppy owners make statements as such: “I just sent my puppy out at 5PM, my puppy had the opportunity to defecate, but he didn’t. I then served him dinner when we came back in, and just an hour later, he had an accident on the carpet! Arrgh.. wasn’t he supposed to be able to hold it for 4 hours?” Being aware of the gastrocolic reflex can help new puppy owners attain success because they’ll send their pups out after their pup’s schedule meal times, which is when they’re more likely to defecate. Other times pups should be taken out is after a nap, Soon, puppies will learn to associate going outside with the act of eliminating, a win-win situation for all!

Did you know? The veterinary term for the excretion of urine is “micturition.”

References:

Katherine A. Houpt, Domestic Animal Behavior for Veterinarians and Animal Scientists

Thomas Colville DVM MSc, Joanna M. Bassert, VMD Clinical Anatomy & Physiology for Veterinary Technicians, Mosby 2002

Nicholas Dodman, Puppy’s First Steps, Houghton Mifflin Company, Boston New York, 2007

[otw_is sidebar=otw-sidebar-1]