Dozens of penguins died after being attacked by insects on Sept. 17.
Sixty-three endangered penguins were discovered dead on a beach at the Boulders African penguin colony.
South African National Parks (SANParks) discovered their lifeless carcasses near Simonstown, 40km (25 miles) south of downtown Cape Town.
A post-mortem revealed the African penguins suffered several bee stings. Cape honey bees are the main suspects since many dead insects were recovered during preliminary investigations.
Penguin samples are still being examined for other “toxicity possibilities and diseases” to rule out other possible causes.
“After tests we found bee stings around the penguins’s eyes,” the Southern African Foundation for the Conservation of Coast Birds said according to France 24.
SANParks was surprised to learn bees might have killed the seabirds.
“Usually the penguins and bees co-exist,” SANParks marine biologist Alison Kock said according to the New York Post. “Bees do not sting unless provoked–we are working on the assumption that a nest or hive in the area was disturbed and caused a mass of bees to flee the nest, swarm, and become aggressive.”
African penguins are an endangered species due to rapid population decline. The International Union for Conservative of Nature blames the decline on food shortages, commercial fishing, and climate change.