Archaeologists have discovered nearly eight million canine mummies -- from hours-old puppies to adult dogs -- in the dark, spectacular catacombs next to a temple of Anubis, the jackal-headed god of death, Live Science reports.

While animal cults are a widely recognized feature of ancient Egypt, not a whole lot is known about the nature of the catacombs and mummies associated with temples dedicated to animal gods. A new study, published in Antiquity this month, chronicles the catacombs of Anubis at North Saqqara: from their heyday during the Late Period (664 to 332 B.C.E.) to their exploitation for raw materials during modern times, where mummies may have been used as fertilizer.

The temple is in the country's ancient capital of Memphis. "When you go to Saqqara now, you see an area of attractive desert with the pyramids sticking up and one or two of the prominent monuments" associated with animal cults, Cardiff University’s Paul Nicholson tells Live Science. But during the Late Period, "it would have been a busy place... a permanent community of people living there supported by the animal cults." These would have included priests, merchants, and tour guides, as well as people breeding animals that will later be mummified as expressions of gratitude for the gods.

The canine catacombs were first documented in 1897, but it wasn’t until 2011 that Nicholson and colleagues began conducting a full excavation of its long series of dark tunnels. The center passageway stretched for 173 meters (568 feet), with the corridors branching from it reaching a width of up to 140 meters (459 feet). These catacombs were constructed from Lower Eocene stones dating back some 50 million years, and the catacombs themselves were built in the fourth century B.C.E. In fact, the ceiling even contained the 48-million-year-old fossil of an extinct marine vertebrate -- likely the relative of today’s manatees.

Many of the mummies have disintegrated over the centuries, and others were disrupted by graverobbers and quarrymen. Still, it was clear that this animal cult was a big part of the economy. Some of the older dogs that had more elaborate burials may have lived at the temple. But many of the dogs were just days, even hours, old when they were mummified: They were likely separated from their mothers and died from dehydration or starvation. "They probably weren't killed by physical action,” Nicholson says. “We don't have evidence of broken necks that you get with cat burials."

While 92% of the mummified remains belonged to dogs, the team also found jackals, foxes, falcons, cats, and mongooses. They’re not sure why these other animals were there: Maybe the dog-looking animals were interchangeable, and there might be a mythological rationale behind the cats and birds.

[Via Live Science]

Images: P.T. Nicholson et al., 2015 Antiquity (middle)