The Secret Life of Puppies

In their first few weeks, the various changes that will create an astonishing array of shapes and sizes start to develop. Ruby the toy poodle's huge personality belies her diminutive frame. Dalmatians Daphne and Digby start to develop the spots that will mark them out for life. Tiny teeth and insatiable appetites support two fast-growing Dogues de Bordeaux.

How a pup's emotional needs develop and how its environment affects it, including developing human-canine bonds, socialising with other dogs, and the trauma of being separated from your littermates and being placed in a house with resident adult dogs.

The documentary explores how dogs learn to communicate with each other, and their owners. While barking might seem like the most obvious way dogs can `speak', canines communicate far more frequently with their ears, eyes, tail and snout, in accordance with a strict code of behaviour. Here, future show-dog Ace - a five-week-old corgi - demonstrates an impressive array of yelps, growls, leaps and squeaks, and pointer Molly begins elementary training with her owner, but struggles to grasp whether human gestures and commands are being addressed to her.

The development of puppies' senses. The dalmatian litter has reached six weeks old. As a breed they are susceptible to deafness, so they are taken for to the vet for a crucial hearing test. A new litter of golden doodles reveal how puppy eyesight develops week by week, cameras track the progress of a springer spaniel as he begins training to become a mountain search-and-rescue dog, and the labrador puppies reach six weeks old - time to find out if they have the senses and skills to pass their guide dog test.

The canine development documentary continues by exploring how puppies use their key senses - smell, touch, sight and hearing - to absorb information about their new surroundings, and crucially, make a start on broadening their horizons. Six-week-old golden retriever Dakin demonstrates how his ever-developing brain helps improve his stature and coordination, and a litter of bull mastiff pups are left baffled by a mirror. A cocker spaniel destined to become a working dog illustrates how selective breeding can encourage desirable abilities, and a corgi with a big future as a show-dog must first overcome a few crucial hurdles.

The documentary concludes, offering an insight into the final stages of a puppy's early development. This time, the focus falls on how fun, engaging activities help young canines to improve their ability to learn - and their general state of happiness. The programme also reveals how the domestic dog has evolved in a unique manner that allows it to find enjoyment in helping human companions to complete difficult tasks.