A passion for the natural world drives many of our adventures. And when we’re not outside, we love delving into the discoveries about the places where we live and travel. Here are some of the best natural history links we’ve found this week.
The killer whales that eat sharks: Since 2017, a pair of male killer whales has been targeting great white sharks near the Gansbaai coast, South Africa. The orcas, named Port and Starboard, have killed at least eight great white sharks in the last five years.
People have found the bodies of the sharks sporadically washed up on beaches. In each case, they have been torn apart, and their livers are gone. Though orca attacks like this are not rare, it is unusual for two whales to be so prolific.
The appearance of the two orcas has had a dramatic effect on shark populations in the area. Before the orcas arrived, between three and eight tagged sharks were seen in the area each day. For months after the first attack that dropped to zero. Tagging data showed sharks swimming hundreds of miles away from the region after an orca attack. In some cases, sharks stayed away for six months or more before returning.
Dogs evolved from two different populations of wolves: Researchers agree that modern dogs evolved from grey wolves 15,000 years ago, but very little else about their domestication is known. Researchers have now discovered that modern, domesticated dogs evolved from two separate populations of ancient wolves. One group was from eastern Asia and the other from the Middle East.
There are two potential scenarios as to how dogs became domesticated. The first is that two distinct domestication events happened, one in each location. The second is that humans domesticated dogs in one of the regions and then bred with wolves in the other, causing the mix of their DNA. “We can’t tell [the two different] scenarios apart. But we can say that there were at least two source populations of wolves,” said evolutionary genomicist Anders Bergström.
The study involved researchers from 16 countries, sequencing the genomes of 66 ancient wolves from Europe, Siberia, and North America.
Astronauts struggle to recover bone density back on earth: While in space, astronauts lose decades worth of bone mass and don’t recover in the first year back on Earth.
Every four weeks in space, astronauts lose 2% of their bone mass due to the lack of gravity and pressure on their bones. New research also shows that the longer the astronauts are in space the longer it takes them to recover. Dr. Steven Boyd, director of the McCaig Institute for Bone and Joint Health, has said these findings are a big concern for future missions to Mars. “Will it continue to get worse over time or not? We don’t know. It’s possible we hit a steady state after a while, or it’s possible that we continue to lose bone.”
Models suggest that during a three-year flight to Mars a third of astronauts would be at risk of developing osteoporosis.
Photo: Sea Shepherd
Can former pirates help scientists study the ocean?: For decades the conservation group, Sea Shepard, took protecting the world’s ocean into their own hands. They sank whaling ships and took on illegal fishing boats.
International courts declared their leader a pirate and terrorist, Interpol said he was an internationally wanted fugitive. Over the last eight years, under new leadership, they have transformed. Now they are trying to protect the oceans using science.
The group has twelve ships and an annual budget of $20 million. They are now re-kitting their ships and trying to change their image. As many government research budgets are dwindling, Sea Shepard hopes to help. They are ferrying scientists to remote locations, surveying endangered animals, and collecting data on overfishing and pollution.
Human ancestors one million years older than thought: Fossils of our earliest ancestors in South Africa are far older than we previously thought.
The Sterkfontein caves near Johannesburg have provided more Australopithecus fossils than anywhere else on Earth. One of their most famous is ‘Mrs. Ples’, found in 1947. It is the most complete skull from this period. Previous analysis dated the skull to 2.1 to 2.6 million years old. But many in the field were not convinced by this.
Researchers know that homo habilis was in the same region 2.2 million years ago, but there are no signs of this in the caves. Then new research showed that ‘Little Foot’, an almost complete skeleton from the period, was 3.67 million years old.
“It was bizarre to see some Australopithecus lasting for such a long time,” said geologist Laurent Bruxelles. New investigations used cosmogenic nuclide dating. Scientists looked at levels of radioactive isotopes in the sediment where the fossils were found. The results suggest ‘Mrs. Ples’ and the fossils found near her are 3.4 to 3.6 million years old.
Photo: Nippon Foundation / Seabed 2030 / BBC
A quarter of the sea floor is now mapped: During the second UN Ocean Conference it was announced that 23.4% of the ocean floor has now been mapped.
Though efforts to map the sea have increased, the vast majority of this came from previously known data. Multiple companies, governments, and institutions allowed their archived data to be used. Seabed 2030 is trying to put together all of the information and create a complete map of the ocean floor.
Previously, institutions and governments were concerned that providing access to their information would give away defense secrets. “They really needn’t worry, one of the messages we’re trying to get across is that we don’t require high-resolution data. One depth value in an area the size of a European football pitch, 100m by 100m or thereabouts, isn’t going to give away national or commercial secrets,” said Jamie McMichael-Philips, the director of Seabed 2030.
