they were aged 30 to 41 months at the time of the survey.

The age at measles vaccination (in months) was derived in calendar time from birth and measles vaccination dates. The analysis included 3604 children for whom information on measles vaccination was available. Doses received after 30 months of age were not considered as the youngest children from the sample were 30 months old at the time of the survey. Overall, 4% of children got their first dose of measles-containing vaccine prior to their first birthday and the majority of them were vaccinated at 11 months of age. For children whose first dose was given before 11 months of age, the second dose was referred to as a first valid dose. Children were classified in various age at vaccination categories: 11 months of ageand whale ribs were used as runners for sleds. Houses were built of whale bones; in Siberia, ribs formed arches above a stone wall, the long heavy jawbones sustaining the weight of the structure. Walrus hides were laid over the bones and lashed to the whale vertebrae. The Inuit could spend the winter riding on whales.

Eskimo string figures were used to capture the sun before it disappeared for the winter. This figure represents a stranded whale and a hungry fox. When the thumb and index fingers are moved, the fox is chased away.

The earliest kayaks, _baidarkas_ in Russian, had whale-bone frames covered in sealskin. For modern kayakers used to a rigid hull, the give in the skin might seem unsettling at first. Joseph Lubischer described the flexibility of