Yaounde, Cameroon - For years, traffickers fuelled the slaughter of gorillas and chimpanzees in Cameroon's rainforests to meet demand for bush meat - an activity conservationists feared could wipe out the great apes in the wild in a few decades.

But now they fear a far worse scenario is taking place.

A previously unknown trade in ape heads, bones and limbs - rather than full bodies for meat - is encouraging poachers to kill more animals than previously done, and wildlife law enforcement officials say it is speeding up population decline.

"We may be looking at something that is developing down the road of ivory trafficking," said Eric Kaba Tah, deputy director of the Last Great Ape Organisation (LAGA), a non-profit wildlife law enforcement body based in Cameroon's capital, Yaounde.

"Gorillas and chimpanzees were hunted mainly for bush meat. The babies were captured and sold as pets. Heads and limbs were cut off and left behind because they resemble human parts," Tah told Al Jazeera.

However, a new picture has now emerged.

If the situation continues, great apes may no longer be around in 10 to 15 years. - Eric Kaba Tah, Last Great Ape Organisation

"What we are seeing increasingly is that poachers are recovering the heads and limbs of chimps and gorillas and leaving the bodies behind to rot," said Tah.

"Limbs and heads fetch more money and if they think the body is going to be a burden to remove from the forest, they simply abandon it and bring out only the high-value products."

'Mystical practices'

Anti-poaching campaigners fear this trend will increase pressure on the already dwindling population of gorillas and chimpanzees, and are warning the great apes could disappear "in our lifetime".

"Body parts are easier to conceal and transport. Because of this, poachers will be tempted to kill more animals than they already do," Tah said.

The exact number gorillas and chimpanzees roaming Cameroon's forests is difficult to estimate because researchers have conducted few studies. But wildlife officials say there are only a few hundred per species. One estimate puts the number of Cross River gorillas in the wild at less than 300.

In the past four months alone, game rangers and security forces have arrested some 22 ape traffickers with a total booty of 34 chimp skulls and fresh heads, 24 gorilla skulls and heads, and 16 ape limbs, according to LAGA. Others have been arrested with jaw bones and other parts.

"If the situation continues, great apes may no longer be around in 10 to 15 years," Tah said.

It is still unclear what is driving the demand for ape parts. However, wildlife officials and anti-poaching campaigners say they have found a connection between the illegal trade and Nigerian communities inside Cameroon and across the border.

"We think ape products are being used for mystical practices," said an official at the ministry of forestry and wildlife, who did not want to be identified because he was not authorised to speak to the press.

Officials say trade in ape heads and limbs is driven by demand from Nigeria [Eugene Nforngwa/Al Jazeera]

Organised, cross-border crime

Trade in ape parts is not entirely new, though it is only recently that law enforcement agents have uncovered "sophisticated and well-organised" trafficking of ape skulls, heads, limbs and bones.

"The more we crackdown, the more we see things that were unknown to law enforcement officials," said Tah, whose organisation has been helping the government of Cameroon to fight wildlife crime for the past 10 years.

"We decided to focus on the trade in ape parts this year, and as a result we uncovered the magnitude of an old phenomenon," said Ofir Drori, founding director of Eco-Activists for Governance and Law Enforcement.

"If we had done this in Congo, Gabon, Democratic Republic of Congo, Central Africa Republic or [any] other country, I am sure we would get the same result. The work in the last months in Cameroon has shown how organised and socialised the ape trade is, and exposed a worrying magnitude," Drori told Al Jazeera.

Traffickers were mainly small-time poachers and dealers, police official Julius Anutemet said. But over the years, they have become skilled, well-funded and organised. Networks now run across the border to big cities in neighbouring Nigeria and a few powerful people could be involved.

"These are professional traffickers, people who live entirely off the trafficking they do," said Anutemet, who has hunted wildlife traffickers since 2003 and made about 580 arrests.

"They have people who supply them with cash and ammunition. They know where the checkpoints are; what roads to take in the forest to avoid being caught. They have men [advising] them about the position of the police and forest guards."

Traffickers are now arrested on a weekly basis. Yet, the crime goes on.

"Our objective is to get the big dealers," Tah said. "When you cut off the head, the body dies. The more you get people up the chain the more successful you are."

Corrupt legal system

Catching people up the chain is often easier said than done, Tah admitted. Widespread corruption means the powerful men behind the crimes are never caught, or get away with "ridiculous fines".

Wildlife traffickers arrested with ape skulls during a crackdown in Cameroon [Eugene Nforngwa/Al Jazeera]

"When you see some court decisions, you are forced to ask if there are other reasons other than legal considerations," Tah said.

The penalty for illegal poaching and trade in protected wildlife is one to three years imprisonment, or a combination of jail time and a fine of up to $20,000. But anti-poaching campaigners say arrested traffickers often walk away with less than the minimum punishment.

"Wildlife crimes are still not viewed as serious crimes in Cameroon, even by officials involved in fighting the crime at the level of the state," Tah said. "Officials arrest and release people on grounds that are not very clear. We have arrested people who had been arrested in the past but let go."

LAGA estimates that corruption is a factor in about 80 percent of the legal cases the organisation has helped to build.

"The illegal trade in apes is rooted in corruption and complicity," said Drori. "These are the real enemies we fight. What drives the extinction of our closest relatives is greed."

"Enforcement has to be stepped up with only one target in mind - [the] number of traffickers put behind bars. The law must be enforced - or we lose these magnificent creatures forever in our lifetime."