A recent study in the journal Molecular Biology and Evolution identified one small but significant difference between humans and apes: their spit. The results enlarge the widening gap observed between humans’ and nonhuman primates’ physiology.

UPDATE (3:25 p.m.): A gunman, who was a student at Saugus High School in Santa Clarita, Calif., killed two students and wounded three others before turning the gun on himself. No details on a motive were released, but authorities noted that Thursday was the shooter’s 16th birthday. The unidentified gunman, who used a .45 caliber handgun pulled from his backpack, is being treated for a gunshot wound to the head at a local hospital.

A federal judge in Texas slapped a $50,000-a-day fine on the state for failing to protect children in foster care. A lawsuit claims the Texas Department of Family and Protective Services (DFPS) suffers from overburdened caseworkers and lack of oversight, resulting in children who leave the system and go into homelessness, poverty, and worse.

Americans are moo-ving on from milk. The country’s biggest dairy company filed for bankruptcy on Tuesday. Dallas-based Dean Foods said it may sell its business to the Dairy Farmers of America, a farmer-owned marketing cooperative.

High school senior Tanner Soracco received a sweet surprise last week. He had painted his parking space at Oxford High School in Connecticut with the Reese’s Peanut Butter Cup logo in honor of his favorite candy.

CHICAGO—An “arctic airmass” from Siberia will bring record lows to the Midwest on Tuesday and Wednesday. The snow that blanketed the region has moved into parts of the Northeast, which could see up to a foot of frozen precipitation and “hazardous travel conditions,” according to the National Weather Service.

The innermost planet in the solar system will make a perfect bullseye when it crosses the sun on Monday. The event, which began at 7:35 a.m. EST, lasts 5½ hours and will be visible in the eastern United States and Canada, and Central and South America, weather permitting.