Blue whales are genetically healthy but are breeding with fin whales, study suggests (1:03) Researchers have sequenced the genome of a blue whale that washed up in Newfoundland in 2014, and used it to do a comparative study of North Atlantic blue whales. A team led by Mark Engstrom, curator emeritus at the Royal Ontario Museum found that despite their small population, the whales are genetically diverse and connected across the north Atlantic, but that on average blue whales from this group are, genetically, about 3.5 per cent fin whale. The work was published in the journal Conservation Genetics. Sea otters’ ravenous appetite for crabs is reshaping a California coastal marshland (10:10) The return of sea otters to salt-marshes on the California coast has halted the erosion of the marshes that occurred in their absence. Without otters, crabs quickly overpopulated and made the area look like “Swiss cheese” by burrowing into the marsh sediments and eating the vegetation’s root system. Brent Hughes from Sonoma State University said their study demonstrates the importance of predators in maintaining the integrity of these vulnerable salt-marshes to boost climate change resiliency along the coast. What will become of our solar system as our sun evolves into a white dwarf star? (19:03) Over many billions of years our sun, and stars of similar size, will first swell into a red giant star, and then contract into a small, dense white dwarf star. A new study using the James Webb Space Telescope has surveyed nearby white dwarf star systems to understand the fate of their planets, and astronomer Susan Mullally says this can help predict our planet’s fate as well. Permafrost has shaped Arctic rivers — and as it melts much will change (27:23) A satellite survey of the frozen north has demonstrated how much permafrost has shaped the landscape, by limiting the number of rivers that can carve into the frozen land. Geoscientist Joanmarie Del Vecchio warns that as permafrost melts, the waters will find many more paths, and this could unleash carbon equal to the annual emissions of 35 million cars for every degree of warming. The research was published in the journal PNAS. Understanding the evolution of what came first, the chicken or the egg (35:44) While the marine ancestors of all terrestrial vertebrates laid eggs in the water, scientists long thought that the first terrestrial animals must have been laying eggs to conquer life on land. In an attempt to untangle this mystery, scientists compared extinct and living animals to trace how far back in their evolution the first egg-layers appeared. Michael Benton, from the University of Bristol, said their study didn’t discern if the first land animals were laying soft-shelled eggs or giving birth to live young, but hard-shelled eggs like modern bird eggs came much later. In the Australian Alps, egg-laying lizards from the valleys breed with live-birth bearing lizards from higher up in the mountain to create hybrids with traits across the whole spectrum in between. Katherine Elmer, from the University of Glasgow, described her study of this population that allowed them to identify the genetic differences between laying eggs and giving birth to live young.