The truth is beautiful in Buttermilk Creek. That was the Texas site of a recent major archaeological find. In the village of Salado, just a couple hundred metres downstream from an important cache of artifacts of the early American Clovis people, anthropologists uncovered something just a few centimetres deeper1. In geological terms, that usually means older – and the assortment of stone tools found by Mike Waters and his team might be the definitive evidence needed to overturn the longstanding “Clovis first” theory.
“Clovis first” is the idea that North America was initially populated by a group of big game hunters known for their interchangeable fluted spear tips – a portable tool that fit well with the nomadic lifestyle. I won’t get into the details (see elsewhere), but many researchers now believe that other migrant groups arrived from the north well before Clovis domination. For example, fishing tools found in California’s Channel Islands provide evidence that a seafaring clan made its way south by hopping along the coastline2.
I also won’t cover the Buttermilk Creek find (again, see elsewhere for this). But there is a poetic element to this discovery worth sharing. The proof that the Buttermilk Creek people arrived ahead of Clovis hunters comes, not from the usual radiocarbon dating methods, but from dating the rainbow.
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It can be easy to see intelligence in the animals we spend a lot of time with. Everyone has their pet example, one of the most common being dogs who can anticipate the precise time of their owners’ return. But what does this really say about the mental life of dogs? Some birds are capable of even more impressive mental stunts – only they often go unnoticed in the wild. Two recent field studies in Africa and Australia provide a nice illustration. The results challenge our notion of limited animal intelligence, but as we will see, the way we interpret them might say more about our own minds than it does about the birds.
Fork-tailed drongos are masters of deception. These small, glossy black birds from southern Africa are known for their ability to mimic the calls of other bird species – much like the mockingbirds found throughout the US and parts of southern Canada. Most of the time, drongos forage alone hunting insects, but occasionally they get other animals to do the hard work for them. Drongos will follow groups of meerkats and pied-babblers – mammals and birds known for their highly social lifestyles – and steal their food, a process known as kleptoparasitism. It might not be a complete loss for the victims, either. Drongo thieves give plenty of alarm calls along the way, and these may help the meerkat and babbler groups avoid predation1.
Perhaps not surprising for an accomplished mimic, the fork-tailed drongo has a diverse alarm call repertoire that includes its own unique warning “chink” as well as the calls of several other bird species. On the savannahs of the Kalahari Desert, birdwatchers noticed that drongos often seem to use these mimicked calls during kleptoparasitism, swooping in to steal food from pied-babblers immediately after sounding a false alarm1. For Tom Flower at the University of Cambridge, this was fascinating anecdotal evidence, so he set out to test whether these alarm calls are used by the drongos in a deceptive way2.
The first thing Flower needed to do was eliminate the possibility that the drongo false alarms are coincidental. If the drongos are truly deceptive, the calls should only occur when the birds are attempting to steal food. Flower also had to establish that the drongos sound the same, regardless of whether they are using their alarm calls in an honest or deceptive context. Finally, he had to show that the meerkats and babblers respond similarly in both cases.
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