The National Zoo will cut its hours starting Jan. 1, opening later in the mornings and closing earlier at night.

The zoo will go from being open 98 hours a week in the summer and 84 hours a week in the winter to 77 hours a week in the summer and 63 hours a week in the winter.

The cut of more than 20 percent of the zoo’s hours was a decision based on safety, Director Dennis Kelly told The Washington Post on Friday.

The zoo is popular among runners and joggers for its 2.5 miles of trails, not just its pandas and other critters. Kelly said that those joggers tend to collide with the many vehicles that bustle around the zoo ferrying food, keepers and veterinarians to the animals, especially when it’s not quite light out in the early hours of the morning.

“We’ve had for some time, going back years, increasing concern about safety and security,” Kelly said. “We’ve observed many near misses for walkers and joggers, particularly in the dark. We’ve had joggers with headphones bumping into parked vehicles.”

Under the new hours, the zoo grounds will open at 8 a.m., not 6 a.m. They will close one hour earlier at night — 5 p.m. instead of 6 p.m. in the winter, 7 p.m. instead of 8 p.m. in the summer.

As a trade-off, the exhibit buildings where some animals are housed indoors will start opening at 9 a.m. instead of 10 a.m. Their winter closing time, however, will be moved half an hour earlier, to 4 p.m.

The bike path through Rock Creek Park that passes through the zoo will remain accessible to the public from dawn to dusk, Kelly said, even when the zoo is not open.

Kelly said he knows that some people who get their morning run in at the zoo will be disappointed.

“I’m a neighbor. I understand your frustration, but I run a zoo,” he said. “Our mission as a zoo has to focus on safety and security.”

He added, “I’m just not going to wait and have a tragedy here.”

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