From terrorists to drug traffickers, detection dogs are trained to sniff out the most elusive of offenders. Now a springer spaniel called Freya has taken up the scent of another slippery species: the great crested newt.
Sheltering in underground burrows and rocky crevices, these warty amphibians are a protected species under rules overseen by Natural England. Boris Johnson previously complained that newt-counting delays had become “a massive drag on the prosperity of this country” because building developers must search for, and move them, before construction projects can begin.
Yet, while much is known about the newts’ aquatic life phase, detecting them during their terrestrial phase is challenging because they spend so much of their time underground, limiting the effectiveness of these conservation policies and practices.
Rising to this challenge, Nicola Jayne Glover, an ecology PhD student at the University of Salford, UK, and her colleagues trained Glover’s English springer spaniel, Freya, to learn the odour of live newts by channelling their scent through open pipes of varying lengths. They also put newts in breathable tubes and buried them under 20cm of clay or sandy soil for Freya to detect, with small ventilation holes in some of the soil samples to mimic newt nesting burrows.
Over 16 trial runs, Freya was able to detect great crested newts up to 2 metres away, with an 87% success rate. She was fastest at detecting newts through clay soil with ventilation, and could tell them apart from other creatures, including frogs and other newt species. When Freya sniffed out a great crested newt, she would signal this to her handler by lying or sitting down.
Although dogs have previously been trained to detect giant bullfrogs – which also occupy underground burrows – and are routinely used to help locate buried human remains, this is the first study which explicitly investigates the influence of different soil types on dogs’ ability to locate underground amphibians.
“Our study provides a general baseline for the use of detection dogs in locating T. cristatus and similar amphibian species during their terrestrial phase,” said Glover, whose results were published in Plos One.
She believes newt-identification is a task that many dogs could be trained to do, and has already trained her other dog, a springer-cocker spaniel named Newky, to do so. Freya and Newky have already saved the lives of countless newts, Glover said.
The great crested newt is the UK’s largest newt, reaching a maximum adult overall length of up to 17cm. It takes its name from the striking, jagged crest that males display in the spring breeding season.
Anyone found guilty of disturbing the newts’ resting places and breeding sites, or taking their eggs, faces an unlimited fine and up to six months in prison.
• This article was amended on 12 June 2023. An earlier version said that great crested newts reached an adult overall length of 17m; this should have been 17cm. The photograph was also changed as an earlier image showed a smooth newt.
