As It Happens | What killed and ate a really big shark? An even bigger shark, scientists say 

When marine biologist James A. Sulikowski started monitoring the migration and mating habits of porbeagle sharks, he didn't expect he would end up investigating a murder mystery.

But when Penelope, a 2.4-metre-long porbeagle, dropped off his research team's radar, he and his colleagues ultimately concluded that she met a grisly fate as someone's dinner.

Their primary suspect? Another, even bigger, shark. 

"Penelope was a big shark, and to think that something large ate her is kind of scary," Sulikowski, director of Oregon State University's Big Fish Lab, told As It Happens host Nil Köksal.

The Dose | Why should I be concerned about mosquitoes?

Experts are warning Canadians about the risk posed by mosquitoes due to environmental factors like climate change. Dr. Sumon Chakrabarti, an infectious diseases specialist with Trillium Health Partners in Mississauga, Ont. explains what we need to know about mosquito-borne diseases, including West Nile Virus. 

CBC Music Playlist | Polaris Picks 

Celebrating the best of Canadian music from 2024. The Polaris Music Prize awards the best full-length Canadian album based on artistic merit, regardless of genre, sales, or record label.

Hear this year's short-list nominees: The Beaches; Elisapie; BAMBII; Jeremy Dutcher; Allison Russell; TOBi; DijahSB; Cindy Lee; Charlotte Cardin; Nobro; and past year's winners!