Canine Companionship: Humans bond with dogs as if they are children

Image via Buzzfeed

Nothing is stronger than the bond between a mother and child... and between dog and human? Although I have not personally experienced motherhood, I recently added a new family member; a four-month-old rescue puppy named Linus (after one of my role models and great chemical engineers, Linus Pauling). When he looks into my eyes my heart melts a little, and I just want to scoop him up and hug him. These feelings are helping me understand why people refer to their dogs as “fur babies,” showering them with toys, treats, costumes, and even pushing them in strollers.

My new puppy, Linus

Now science explains why dogs really are “Man’s Best Friend.” When people refer to their dogs as their kids, they aren’t too far off. A new study in Science shows that humans and dogs actually share a unique bond, mediated through the love hormone, oxytocin. What makes dogs so special to us, and how did this symbiotic relationship begin?

Dogs were the first animal to be domesticated by humans

Image credit Dan Burr via Flickr

The dog-human relationship has a long history. Dogs were domesticated by humans before any other plant or animal, including food crops or livestock like horses and cattle. Scientists know that dogs evolved from the gray wolf, however they are still trying to figure out where and when they became friends with humans. The consensus among scientists is that dogs and humans began their relationship somewhere between 15,000 and 30,000 years ago during the Paleolithic era.

Charles Darwin, the man responsible for the theory of evolution, theorized that dogs initiated their relationship with humans, following them to scavenge their leftover animal carcasses and scraps. Eventually, dogs evolved to be more and more trusting of humans. The less fearful and friendlier dogs lived longer, evolving to become the human-like pets we know today that sit on our furniture, ride in cars, coexist (hopefully) with our other pets, and understand our language; although, we must remember they still have some wolf-like instincts from their ancient ancestors.

Image via quickmeme.com 

Dogs have evolved to be the most responsive animal to human body language. For example, dogs are the only animal that understand what humans mean when they point at something with their hand - “look at that.” They respond to human cues and words, along with eye contact. Not even other primates can understand our complicated social cues to that extent. Why are dogs so unique in this aspect? A new study from researchers in Japan shows the feelings of companionship we have towards dogs are a result of direct eye contact.

Dogs manipulate the human feelings by staring at us

Image credit: B Rosen via Flickr

When dogs and humans stare at each other, the love hormone, oxytocin, is produced. This relationship has evolved to create a bond between human and dog similar to the bond a mother and child have. Oxytocin is related to the feelings of love and comfort between humans, which you can read more about in this Valentine’s Day post. A new study by a group at Azabu University in Japan has linked the oxytocin hormone to the bond that humans and dogs have.

Increased levels of oxytocin are positively associated with increased social behavior towards both humans and other dogs. According to several studies, after dogs and their owners interact, oxytocin levels increased in both the dog and its owner. The Japanese researchers, however, showed that oxytocin increased the most after dogs and their owners share a mutual gaze for a sustained period of time, more than talking or touching.

To further solidify their findings, the researchers also artificially administered oxytocin to dogs and then had them interact with their owners. Dogs given oxytocin stared at their owners more than the dogs not administered oxytocin. Following the interaction, the dogs given oxytocin and their owners both showed an increased production of the hormone after the interaction. This suggests something known as a positive feedback loop, meaning that the more oxytocin present, the more gazing, and the more oxytocin is produced. In other words, it’s like a snowball effect, the more you and your dog stare at each other, the more love there is and the more you want to stare at each other.

A dog and owner gazing at each other

The special bond between a dog and its human is unique to its owner. Researchers also observed dogs interacting with humans who were not their owners, and oxytocin levels were unchanged. Not only is oxytocin production unique to the owner, it is unique to dogs as a species. Wolves reared by humans were studied along with their owners, and no relationship was observed between eye contact and oxytocin levels.

All of these observations suggest dogs have a unique neurological pathway specific to human bonding, which they have evolved over tens of thousands of years with us. They have also evolved to have adorable child-like characteristics to give us the “feels” for them, to put it unscientifically. These findings could also explain why aggressive behavior of dogs towards humans is correlated to their interactions with humans and not their breed. My only question is, why am I attached to my cat in a similar way, and when will he and my dog become friends?

For more information, check out this podcast from Science. 

Human health benefits from furry companions

Oxytocin is currently studied as a treatment for several mental disorders associated with decreased levels of the hormone. To treat these diseases, researchers are artificially administering oxytocin to improve social symptoms of disorders like autism and post-traumatic stress disorder (PTSD). Understanding how dogs can chemically alter our brains gives us an understanding of how and why service animals are beneficial. Assistance dogs can stimulate the production of oxytocin in people suffering from mental disorders.

Image via The Daily Republic

Oxytocin has also been studied to treat other mental disorders like depression, anxiety, and stress. More research is needed to understand more about this link, but for now I will take it as a sign to spend more quality time with my newest 4-legged friend, especially when I am stressed out. So at the end of the day, it might be mentally beneficial to take your furry friend on a walk or jog, play some ball, snuggle on the couch… or just stare at each other.

Image via Giphy

Cheers to your brain and thanks for reading!

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Contraceptives: Let’s talk about SEX (the baby part is your choice)

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Today I want to talk about something that makes a lot of people uncomfortable: sex, birth control, and “nether regions.” These topics are incredibly important to understand and the stigma behind them sometimes prevents that from happening. It is especially important for those making decisions about related policy to understand them.

Most likely your news feed has contained the Hobby Lobby Supreme Court case in recent days. Hobby Lobby refused to comply with the “contraception mandate” contained in Obamacare, citing that it went against their religious beliefs. On June 30, the Supreme Court ruled that Hobby Lobby did not have to provide this coverage, because of freedom of religion. I would like to point out that all of the votes that passed this ruling came from men, who have never had to decide if hormonal birth control was a good fit for their bodies. Disclaimer: This post is not my opinion on that ruling, its goal is to communicate science behind contraceptive use.

So, what exactly is the “contraception mandate?” Obamacare does not require businesses to provide contraception, so the phrase contraception mandate is misleading. Obamacare compliant coverage is required to cover the cost of contraception; that means the insurance plan, and not the business, provides contraception at no extra cost to the employee.  Now, Hobby Lobby employees can purchase contraception, but it will not be covered as part of the plan that Hobby Lobby provides.

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Why is Hobby Lobby against providing contraception? Some companies think that certain forms of contraception are equivalent to abortion, which is against their religious beliefs. Therefore, they reason that they should not “be forced to pay for abortions.” There is a large disconnect between what people know about the mechanisms of various forms of contraception and how they compare to abortion. Whether or not you agree with Hobby Lobby, Obama, or the Supreme Court, it is important to know the science behind different forms of birth control and how they prevent pregnancy, other conditions they can treat, as well as how they different forms can have different benefits.

What happens when a pregnancy occurs?

The female reproductive system (source)

In order for pregnancy to occur, several steps are required (refer to the diagram above):

1.  Ovulation: Eggs grow in the ovaries and about once every month, one of the eggs is released. This is referred to as ovulation. When the egg is released hormones in the female rise to prepare the uterus for the egg.
2.  Fertilization: The egg moves into the fallopian tube and stays there for about 24 hours waiting to be fertilized. When one sperm is implanted into the egg, and a zygote is created. The zygote stays in the fallopian tubes for 3-4 days.
3.  Implantation: The zygote slowly moves from the fallopian tubes to the uterus, where it implants to grow for the gestation period. Once implanted, it is referred to as an embryo, which grows to a fetus. If implantation does not occur, the lining of the uterus is shed, which is what menstruation is.

An abortion (medically speaking) is the termination of the implanted zygote  (referred to as an embryo or fetus). Contraceptives generally work by preventing one of the 3 above steps, before implantation occurs. Each method had advantages and disadvantages, and every person theoretically can choose which method makes the most sense for their life. For more information on any of these methods as well as other reproductive health care I encourage you to visit the Planned Parenthood website.

A summary of the mechanism, cost, and effectiveness of common forms of contraception. Failure rate is a percentage.

Barriers – Prevent fertilization,  $150/year, 12% failure rate

The most widely used method of birth control used in the world is a barrier contraceptive- the condom. Barriers prevent sperm from entering the fallopian tubes to get to the egg. Barrier contraceptives include male and female condoms, diaphragms, spermicide, and contraceptive sponges. Condoms are the only form of birth control that also prevent STIs and HIV. The most effective barrier is the diaphragm, with a 12% failure rate. Barrier methods typically do not have any adverse effects on health unless there is an allergic reaction.

Hormonal birth control – prevents ovulation and fertilization, $120-800/year, 0.05% failure rate

Hormonal birth control (HBC) is widely used throughout the world by women. It prevents pregnancy by releasing hormones that prevent ovulation or fertilization. Currently there is not a form of HBC available for males, but clinical tests are underway. Currently HBC is in the form of oral pills, implants, injections (shots), patches, and vaginal rings. HBC has uses beyond preventing pregnancy. They are often prescribed to women who have conditions as a result of hormonal imbalance, such as irregular or painful periods, migraines, acne, and ovarian cysts. The most effective form of HBC is an implant at 0.05%, with the next lowest being injection at 6%. It can have varying adverse effects on women, depending on the type and dose of hormone. These include mood changes, libido, acne, weight gain, vision changes, and blood clots.

Intrauterine devices – prevents ovulation, fertilization and sometimes implantation, $700-1000 one-time cost, 0.2% failure rate

Intrauterine devices (IUDs) come in two main forms: hormonal and copper. IUDs are small devices inserted into the uterus. This is the only long-acting (6-12 years) and reversible form of contraception.  The hormonal IUD acts similarly to HBC, in preventing ovulation. It also thickens the cervical mucus so that sperm cannot get into the fallopian tubes, preventing fertilization. Copper IUDs cause the uterus and fallopian tubes to produce a fluid containing copper ions, which are toxic to sperm. Therefore it prevents fertilization. It can also be used as emergency contraception by preventing implantation. Copper IUDs are a good alternative for women who have adverse effects with hormonal birth control. The hormone containing IUD has the lowest failure rate at 0.2%, and use with IUDs is almost always perfect.

Sterilization – prevents ovulation and fertilization, $600-6000 one-time cost, 0.15% failure rate

Sterilization is a permanent procedure; either a male vasectomy or a female tubal ligation (tubes tied). In tubal ligations, the fallopian tubes are clamped and blocked or severed and sealed to prevent eggs from reaching the uterus. There are risks for surgical complications during this type of procedure. Male sterilization is called a vasectomy. The male vasa deferentia is severed or tied and sealed to prevent sperm from being released into the seminal stream, thereby preventing fertilization. A vasectomy is less invasive than a tubal ligation and there is 20 times less risk of complications.

Emergency contraceptives – prevent implantation, $30-65/dose, reduces incidence of pregnancy by 90%

Emergency contraceptives can typically be used up to 5 days after unprotected sex. They prevent fertilization or implantation with a large dose of hormones. Another method is the copper IUD, which prevents implantation, as discussed above.

Behavioral – free, 0%-28% failure rate

Behavioral birth control methods include abstinence, withdrawal, and fertility awareness methods. All methods are free, as they only require the two partners.

Are there any contraceptives that medically do cause abortions?

There are several pills on the market that can be used to induce an abortion. Cytotec and Prostin E2 are the most commonly used ones. They induce labor by softening the cervix and causing uterine contractions. These are not considered forms of contraceptives, as they do not prevent pregnancy from occurring. Therefore they are in a different category under Obamacare.

How can I use this information?

There are many forms of birth control out there, and each person has their preference for the method that works best for them. No contraceptive that is covered on Obamacare causes the medical definition of an abortion.

There are many sides to the story of whether or not your employer should be able to choose which forms are covered or not based on their beliefs. Interestingly, Hobby Lobby is willing to cover sterilization, but not IUDs, emergency contraception, or HBC. Barrier methods are often not grouped into “contraception coverage” but perhaps doctors and pharmacies should begin offering more of them at the cost of the insurance companies.

Birth control is a complex and diverse field, with many opinions and options. I encourage you to understand and research each method before determining which is right for you, and before you vote on legislation pertaining to it. Science has given us more choices to prevent unplanned pregnancies in the way that best fits our lifestyle, and continues to do so. 

We have come a long way from condoms made from lamb intestine… cheers to that! Have a safe and fun 4^th of July (and if more than one kind of fireworks fly, you have all the options to fit your needs above)!

Thanks for reading, and cheers to your brain!

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