Weeks before its scheduled official opening, the Wallis Annenberg Wildlife Crossing has already attracted its first unscheduled travelers. A western fence lizard appeared first, followed by two coyotes that explored the immense California structure while construction was still underway.

The vegetated overpass crosses the busy 101 Freeway in Agoura Hills, giving animals a route through their natural range without the danger of a vehicle collision. It measures 380 meters (1,246 feet) long and 240 meters (787 feet) wide.

Those dimensions make it the largest wildlife crossing in the world. The structure spans 10 lanes of traffic, creating a path across a freeway that has divided the surrounding ecosystem for decades.

The bridge is scheduled to officially open to wildlife on December 2, once the slope leading to the crossing has been fully set up. Local wildlife, however, has not waited for the formal invitation.

Rangers had already seen western fence lizards using the structure, making the reptiles its earliest visitors. The first known large mammal arrived later in October, providing another encouraging sign before the crossing officially opens.

On October 27, the US National Park Service recorded a lone coyote climbing the southern slope of the unfinished crossing. Trail cameras captured the animal making its way onto the structure despite the continuing construction activity.

The Wallis Annenberg Wildlife Crossing project shared the discovery on social media. “Because of construction activity, we cannot place any cameras on top of the Agoura Road structure yet. But we do know he explored the top of the 101 bridge for some time. Yay!”

That coyote was not the last early arrival. Another coyote was seen on the structure during the early hours of November 5, adding a second large mammal sighting before the planned opening.

The project responded to the animals’ disregard for the official timetable with another celebratory message. “Apparently, wildlife has its own opening date!”

Although the animals are not following the schedule, their appearances provide a positive indication that the crossing will be used. Scientists have already observed several species regularly traveling along a trail immediately beside the bridge.

Those animals include bobcats, coyotes, gray foxes, mule deer, and mountain lions. Each of those species could benefit from having a vegetated route across the busy freeway and through its natural range.

An array of cameras watches the site and will help document animals passing across it. Biologists from the National Park Service will use the monitoring system to examine how wildlife uses the bridge and how the ecosystem responds to being reconnected.

For the researchers, the scientific work extends beyond simply recording which animals appear. Seth Riley, wildlife branch lead at Santa Monica Mountains National Recreation Area, said the larger question concerns whether the crossing can effectively reconnect the divided ecosystem.

“This is more than just about whether animals use the crossing,” Riley said in a statement. The structure will give scientists an opportunity to study a connection that has been missing for decades.

“We want to understand how effective it is in reconnecting an ecosystem that has been divided by the freeway for decades. That is a much bigger scientific question and answering it will take years,” Riley added.

The Wallis Annenberg Wildlife Crossing has been decades in the making. The effort began in 1990, when a study found that the 101 Freeway had separated the Santa Monica Mountains from the Simi Hills.

That division caused additional problems for the region’s struggling mountain lion population and several other species. The crossing was developed to give wildlife a safer way to move through the area without risking an accident with a vehicle.

After 36 years and $114 million, the project is finally coming to fruition. Its first lizard and coyote visitors have already shown that wildlife is ready to explore the route, even before the final slope is completed and the official opening arrives.