Dog Behaviour – Animal Instinct


Dogs first evolved around 12,000 years ago. They’re one of only about a dozen animals that’s ever shared a close relationship with humans. Today, they vary dramatically in size, shape, colour, and behaviour. At one end of the scale, the Chihuahua weighs in at under a kilogram, compared to the Neapolitan Mastiff, which weighs a massive 70 kilograms. No other species shows such a range of individual characteristics. But regardless of their size, the gestation
period for dogs is the same, about 63 days. We’ll follow a Golden Retriever from conception, right through to birth. And for the first time we’ll be able to
watch the foetuses as they develop within the mother’s uterus. The female Retriever usually releases 10 to 12 eggs. She’s now ready to mate. The dog’s penis contains a bone that may
provide additional stabilisation during copulation. Probably because the male needs rigidity to enter the female, nearly vertically from below. He mounts her. Within seconds he ejaculates. The two animals now enter the tie stage, the male’s penis locks inside the vagina. During this time, more fluid from the prostate gland is released to help transport the sperm. The tie can last from 5 minutes to an hour. They normally turn to stand back to back for this process, this seemingly bizarre behaviour has its roots in the dog’s evolutionary past. Its wild ancestors would adopt this position to protect themselves from attack. Our Golden Retriever’s eggs are now fertilised and travelling towards the uterus. Over the course of just 63 days each of these bundles of cells, will become a puppy in a litter of nine. It’s just over 2 weeks since our Golden
Retriever conceived, and she’s already a quarter of the way through her pregnancy. Inside her uterus an amazing process is underway. The embryonic ball of cells turn in on themselves in a process called Gastrulation. As the cells continue to divide and multiply they need instructions, a trigger to tell them what type of cells they should become, and whereabouts in the embryo they should go. Gastrulation is one of the greatest wonders of nature. First, the embryo folds in on itself to form
a cylindrical tube. As it does so it forms a patch of tissue,
this is known as the primitive streak. On one edge of this primitive streak, another much smaller patch of tissue forms. Biologists call it the organiser. Every cell in the developing embryo then flows over the organiser, as they do they receive instructions that assign them their fate. Some are told to become head cells, some tail cells, others are instructed to form nerve cells, and some become skin. Now the nine embryos attach to the uterine wall, as they do, the uterus contracts to push them along so they’re all evenly spaced. It’s 3 weeks since conception, the embryos are about the size of a pea. Our dog is now showing outward signs of her pregnancy. But even dogs who are not pregnant can sometimes exhibit such signs. This odd behaviour, sometimes referred to as pseudo, or phantom, pregnancy, goes back to the dog’s distant past, for these embryos, along with every dog on the planet, all descend from the grey wolf. In the wild, only the dominant pair in a pack every breeds, ensuring that the strongest bloodline thrives. But the dominant bitch is not only the mother for the pack, she’s the primary hunter too. If she had to stop hunting while rearing her own puppies, the pack would lose her predation skills. To avoid this, every female comes into season together. The unmated bitches go through a false pregnancy. When the dominant female’s pups are born the other females can suckle and graze them, allowing the leader to go straight back to
hunting. The legacy of this behaviour can still be
seen in the domestic dog. During a phantom pregnancy she may start nursing toys, carrying them to her bed area. In some cases she will make a nest, convinced she is about to give birth.

Leave a Comment

Your email address will not be published. Required fields are marked *