Dolphins on the Solomon Islands face a threat that is rare today. Island residents kill the mammals for their teeth, which are used as a currency locally.
Residents of the tiny village of Fanalei in the Solomon Islands killed about 1,600 dolphins for their highly-prized teeth in 2013, according to a new study published in the #link:http://rsos.royalsocietypublishing.org/content/2/5/140524:journal Royal Society Open Science#.
"Detailed records [...] up to the time of our visit, included at least 1,500 pantropical spotted dolphins, 159 spinner dolphins and 15 'bottlenose' dolphins," the researchers wrote.
A summary of all available records from 1976 to 2013 revealed at least 15,454 dolphins were killed by Fanalei villagers who use the teeth as currency, for bride price - a bride equals about 10 dolphins - and as jewelry.
The traditional practice appeared to have stopped around the middle of the 19th century, most likely with the introduction of Christianity, according to the study, but was revived in 1948 and has continued since, despite environmentalists' efforts to halt it.
According to the researchers, the increasing commercial value of dolphin teeth is behind the large numbers of dolphins killed and is creating an incentive for the practice to continue.
"We also found the local price of a dolphin tooth had increased from about US$0.14 in 2004 to about US$0.70 in 2013," the researchers added.
While none of the hunted dolphin species on the Solomon Islands is listed as vulnerable or endangered, the researchers say the large numbers killed pointed to a danger of over-exploitation. They see "an urgent need to improve the monitoring of these catches."
Animal species have been used throughout history as currency - and not only on the Solomon Islands. Squirrel and other animal fur pelts played a vital role in bartering and trading in medieval Russia and Finland and beads handcrafted from whelk and clam shells were the first form of cash in America.
Shells in general are among the earliest known forms of ancient currency. There's the Monetaria moneta - or money cowry - a small shell that even has money in its name.