The twins say they know one another’s thoughts without having to speak. “Talking in our heads” is how they describe it.

BC's Hogan twins, featured in the documentary Inseparable, are unique in the world. Joined at the head, their brains are connected by a thalamic bridge which gives them neurological capabilities that researchers are only now beginning to understand. Still, they are like other Canadian twelve-year-olds; they attend school, have a favourite pet and are part of a large, loving family determined to live each day to the fullest. Here are a few highlights:

Craniopagus twins, joined at the head, are a rarity — one in 2.5 million. The vast majority do not survive 24 hours. Krista and Tatiana Hogan were born October 25, 2006, in Vancouver, B.C.

A CT scan of the twins showed they could never be separated due to the risk of serious injury or death.

The structure of the twins’ brains makes them unique in the world. Their brains are connected by a thalamic bridge, connecting the thalamus of one with that of the other. The thalamus acts like a switchboard relaying sensory and motor signals and regulating consciousness.

Krista and Tatiana Hogan share the senses of touch and taste and even control one another’s limbs. Tatiana can see out of both of Krista’s eyes, while Krista can only see out of one of Tatiana’s.

Tatiana controls three arms and a leg, while Krista controls three legs and an arm. They can also switch to self-control of their limbs.

The twins say they know one another’s thoughts without having to speak. “Talking in our heads” is how they describe it.

The girls are diabetic and have epilepsy. They take a regimen of pills, blood tests and need daily insulin injections.

The twins go to a regular school and as of September 2017 have started Grade 6. Though academically delayed, they are learning to read, write and do arithmetic.

The twins have three siblings: Sisters Rosa and Shaylee and a brother Christopher, also known as Toad.

The girls have very different personalities. Tatiana is outgoing, talkative and high strung while Krista is quieter, more relaxed and loves to tell jokes.

The girls ride a specially-built bicycle, zoom down hills on toboggans, cross country ski and, as part of their physical therapy, are learning to swim.