CALGARY - The Calgary Zoo says most of its nine surviving stingrays appear to be slowly improving, but it's no closer to finding out what suddenly killed 34 of the creatures last weekend.
Zoo spokeswoman Laurie Herron says two of the zoo's prized cownosed rays have begun feeding again, others are showing signs of improvement, but one remains quite sick.
The zoo is still waiting on preliminary water tests to come back, but more detailed toxicology reports could take upwards of two months.
Veterinarians suspect possible toxins in the water because of the speed at which most of the animals died.
Twenty-six rays died Sunday just a few hours after showing signs of stress, and eight more died by Monday morning.
Zoo officials have not ruled out foul play at the touch tank that opened less than three months ago and allowed visitors to feel and even feed the rays.