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Sheepdogs found to use two simple rules to herd sheep

Aug. 27, 2014
Courtesy of U.K. Natural Environment Research Council 
and World Science staff

Sheep­dogs use just two sim­ple rules to round up large herds of sheep, ac­cord­ing to a stu­dy: col­lect the sheep when they’re apart, and drive them for­ward when they’re to­geth­er.

Re­search­ers say the find­ings could lead to the de­vel­op­ment of robots that can gath­er and herd live­stock, crowd con­trol tech­niques, or new meth­ods to clean up the en­vi­ron­ment.

The sci­en­tists used GPS tech­nol­o­gy to un­der­stand how sheep­dogs do their jobs so well. Un­til now, it was­n’t clear how the dogs man­age to get so many un­will­ing sheep to move in the same di­rec­tion.

Re­search­er An­drew King of Swan­sea Uni­vers­ity in the U.K. fit­ted a flock of sheep and a sheep­dog with back­packs con­tain­ing ex­tremely ac­cu­rate GPS de­vices de­signed by col­leagues at the Roy­al Vet­er­i­nary Col­lege, Lon­don. Dan­iel Ström­bom of Upp­sa­la Uni­vers­ity in Swe­den and col­leagues then used da­ta from these de­vices, and com­put­er sim­ula­t­ions, to de­vel­op a math­e­mat­i­cal shep­herd­ing mod­el.

The team found that sheep­dogs likely use just two sim­ple rules. In the mod­el, one shep­herd could herd a flock of more than 100 in­di­vid­u­als us­ing those rules. The re­search is pub­lished in the Jour­nal of the Roy­al So­ci­e­ty In­ter­face.

“If you watch sheep­dogs round­ing up sheep, the dog weaves back and forth be­hind the flock in ex­actly the way that we see in the mod­el,” said King, a fell­ow at the U.K.'s Na­tural En­vi­ron­ment Re­search Coun­cil. “We had to think about what the dog could see to de­vel­op our mod­el. It bas­ic­ally sees white, fluffy things in front of it. If the dog sees gaps be­tween the sheep, or the gaps are get­ting big­ger, the dog needs to br­ing them to­geth­er.”

Sa­id Ström­bom: “at eve­ry time step in the mod­el, the dog de­cides if the herd is co­he­sive enough or not. If not co­he­sive, it will make it co­he­sive, but if it’s al­ready co­he­sive the dog will push the herd to­wards the tar­get. Oth­er mod­els don’t ap­pear to be able to herd really big groups – as soon as the num­ber of in­di­vid­u­als gets above 50 you start need­ing mul­ti­ple shep­herds or sheep­dogs.”

King said “there are nu­mer­ous ap­plica­t­ions for this knowl­edge, such as crowd con­trol, clean­ing up the en­vi­ron­ment, herd­ing of live­stock, keep­ing an­i­mals away from sen­si­tive ar­eas, and col­lecting or guid­ing groups of ex­plor­ing robots.”


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Sheepdogs use just two simple rules to round up large herds of sheep, according to a study: collect the sheep when they’re apart, and drive them forward when they’re together. Researchers say the findings could lead to the development of robots that can gather and herd livestock, crowd control techniques, or new methods to clean up the environment. The scientists used GPS technology to understand how sheepdogs do their jobs so well. Until now, it wasn’t clear how the dogs manage to get so many unwilling sheep to move in the same direction. Researcher Andrew King of Swansea University in the U.K. fitted a flock of sheep and a sheepdog with backpacks containing extremely accurate GPS devices designed by colleagues at the Royal Veterinary College, London. Daniel Strömbom of Uppsala University in Sweden and colleagues then used data from these devices, and computer simulations, to develop a mathematical shepherding model. The team found that sheepdogs likely use just two simple rules. In the model, one shepherd could herd a flock of more than 100 individuals using those rules. The research is published in the Journal of the Royal Society Interface. “If you watch sheepdogs rounding up sheep, the dog weaves back and forth behind the flock in exactly the way that we see in the model,” said King. “We had to think about what the dog could see to develop our model. It basically sees white, fluffy things in front of it. If the dog sees gaps between the sheep, or the gaps are getting bigger, the dog needs to bring them together. Said Strömbom: “at every time step in the model, the dog decides if the herd is cohesive enough or not. If not cohesive, it will make it cohesive, but if it’s already cohesive the dog will push the herd towards the target. Other models don’t appear to be able to herd really big groups – as soon as the number of individuals gets above 50 you start needing multiple shepherds or sheepdogs.” King said “there are numerous applications for this knowledge, such as crowd control, cleaning up the environment, herding of livestock, keeping animals away from sensitive areas, and collecting or guiding groups of exploring robots.”