Shark experts who spoke to Channel 5 News say they’re still trying to understand what led to a shark injuring four people on South Padre Island.

The attacks occurred on Thursday. Two people were bitten by the shark, and South Padre Island officials announced on Friday they were out of surgery and remained hospitalized in stable condition.

ORIGINAL STORY: Authorities investigating shark attacks at South Padre Island

One other individual required stitches after kicking the shark while defending his wife. A fourth person received minor injuries and was treated at the scene.

The shark eventually escaped into open waters as authorities tracked it following the attacks.

Shark experts say they are thinking about all factors that could’ve led to this, such as a shark’s annual cycle, where they get their food, warming oceans and loss of habitats.

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“Are the sharks hungrier than normal, are they moving to another habitat or was that really a very, very rare, very isolated incident,” Gladys Porter Zoo Aquatics Curator Kathleen Thompson-Hawk said.

According to Thompson-Hawk, summer happens to coincide with more shark activity.

“This is the time of year when they do come in to shallower water. Some species are breeding, some species are birthing here, so this is exactly where they normally are,” Thompson-Hawk said. “Unfortunately, it's right at the same time of year that we really enjoy going to the beach."

A shark’s pregnancy cycle usually lasts a calendar year, so sharks are breeding around summer and giving birth the following summer, Thompson-Hawk added.

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All experts who spoke with Channel 5 News emphasized that there are more sharks in the water than you can see.

“I tell people all the time if you ever swam in the ocean, you've probably been within 20 feet of a shark,” Dr. Adrian Chappel with Oregon State University said. “99.9% of the time, they are not interested in us at all."

Chapel says sharks are highly mobile, and studies have shown it’s hard to track them.

Experts still want to know all the factors that contributed to the shark behavior so many people witnessed at the island. They also want the public to understand the overall the odds of an attack are very low.

Watch the video above for the full story.