Tarmac Group first listed on the Birmingham Stock Exchange in 1913 and then the London Stock Exchange in 1922. During the 1920s and ‘30s Tarmac had to cope with national strikes, recession and periods of intense competition. Nevertheless, the company gradually expanded its geographic coverage (particularly in the south east), increased its production of paving slabs and moved into road surfacing as well as supply. As with so many companies in the construction industry, the Second World War increased the demand for Tarmac’s services, notably for surfacing the large numbers of airfields being built or modernised. By the time of its half
Cetacean surfacing behaviour Cetacean surfacing behaviour Cetacean surfacing behaviour or breaching is a group of behaviours demonstrated by the Cetacea infraorder when they come to the water's surface to breathe. Time intervals between surfacing can vary depending on the species, surfacing style or the purpose of the dive, and some species have been known to dive for up to 85 minutes at a time when hunting. In addition to respiration, cetaceans have developed and used surface behaviours for many other functions such as display, feeding and communication. All regularly observed members of the order Cetacea, including whales, dolphins and porpoises, show a range