In Chad, the ivory poachers have upgraded to automatic weapons.
Having bolstered the population at this "last stand for elephants" in central Africa, the Wildlife Conservation Society estimated recently that the numbers had dropped again, from 3,500 to 1,000.
Half a world away, San Diego Zoo workers are building a US$44 million elephant exhibit. Its state-of-the-art amenities include a 2.5-acre savannah, a 9-foot-deep pool, and rubber flooring to prevent foot problems.
Clearly, the world's elephants are a study in contradictions.
In the wild, many populations are close to free fall. An estimated 1.4 million African elephants were alive in 1970, compared with about 400,000 today - a loss of about 26,000 a year. In roughly the same time, Asian elephants dropped from 200,000 to 30,000.
"There's a serious question of how long we're going to have elephants on earth," says Paul Boyle, a conservation official at the Association of Zoos and Aquariums, the industry accrediting group.
In North American zoos, the charismatic animals help draw 175 million visitors a year.
But over the past decade, many have questioned whether zoos can meet the physical, psychological and emotional needs of these huge, highly intelligent and socially complex creatures.
A report printed in December in the journal Science reignited concerns. The study compared Asian and African elephants in European zoos with those in Kenya's Amboseli National Park in Kenya and a Myanmar logging operation.
The astonishing conclusion: Despite all the veterinary care and absence of predators, zoo elephants lived only half as long as those in the wilder populations.
Philadelphia lawyer and elephant activist Marianne Bessey says the study "confirms that a life in captivity is devastating for elephants."
But howls of outrage rose from the zoo community.
"The article is a house of cards," says AZA's Boyle, who said the data were misinterpreted. He accused the authors of being anti-zoo.
The study looked at data back to the 1960s - another thing zoo officials objected to because care has advanced significantly since then.
Assessing more recent trends, lead author Georgia Mason, an animal welfare professor at the University of Guelph in Ontario, says lifespans among African zoo elephants are improving.
But for Asian elephants, "the results were pretty clear-cut, and much more worrying."
The median lifespan in zoos was 19 - meaning half die by then, half later. In logging camps in Myanmar, the median age was 42.
Elephants present special challenges for zoos. In the wild, they range over tens or hundreds of square kilometers. Herds of four to 12 related animals stay together virtually for life. In zoos, space is limited and obesity is common. Elephants live in smaller groups and are often transferred between zoos.
In 2001, the AZA instituted new standards for elephant exhibits.
The trend is toward larger exhibit spaces and bigger breeding herds, which complement the ultimate elephant enrichment activity - "babies, and caring for babies," says the Indianapolis Zoo's Deborah Olson, who also is executive director of the International Elephant Foundation.
Since the AZA's new standards, 61 zoos have improved their elephant exhibits or announced plans to do so. But at least half a dozen zoos, including Philadelphia's, decided to close them.
In 2007, Philadelphia's Asian elephant, Dulary, was moved to a Tennessee sanctuary. Now 45, she's "in excellent health," says zoo chief operating officer Andrew Baker.
Philadelphia's African elephants were to be sent to a state-of-the-art conservation center near Pittsburgh.
But last summer, before it was completed, one of them died. At 53, Petal was the oldest African elephant in a North American zoo.
Now Bette, 25, and Kallie, 26, have begun the routine pre-move veterinary testing and monitoring. Depending on weather and transportation logistics, they could move in February.
Advocates say zoo populations constitute a kind of genetic ark for the future. Bette and Kallie are valuable because they were wild-caught in Zimbabwe and have not bred yet.
Bessey and others have long wanted the animals to move to the Performing Animal Welfare Sanctuary in California, to join a herd that roams over 120 acres.
Actually, "wild" is a fading notion. Many elephants are in national parks or other managed areas. When using elephants for logging was outlawed in Thailand, hundreds were stranded. A sanctuary in the north, the Elephant Nature Park, is now a tourist attraction. On both continents, poaching remains rampant.
From the Congo to Borneo, elephants are losing their forest habitats. In Sumatra, it's being converted to palm oil plantations and small farms. Conflicts are inevitable. After a crackdown on poaching in Botswana, South Africa and Namibia, elephant numbers in one national park nearly doubled in five years.
The AZA standards require that zoos with elephants fund conservation efforts. Many funnel money through the International Elephant Foundation, which has spent US$1.4 million on projects since 1999.
Philadelphia has committed US$100,000 over five years to a Borneo group that helps villagers protect their crops. But the sums are dwarfed by what zoos spend to keep elephants in captivity.
In the past decade, Western zoos have spent or committed about US$500 million to improve exhibits for just over 200 individuals, according to Mason.
"These sums are worrying because they're so staggering compared to what it would take to conserve these animals better" in the wild, she says in a Science podcast.
The AZA contends the dire situation in the wild - and a growing disconnect to nature in American culture - makes zoos all the more important.
"When you get a seventh-grader next to an elephant, there's that hay smell. It's huge. They look up and see these eyelashes that are 4 inches long," says the AZA's Boyle. "And they begin to ask questions."
But last month, in an emotional meeting packed with activists, the Los Angeles City Council withdrew its support for the zoo's US$42 million new elephant exhibit.
It all boils down to one thing, Councilwoman Jan Perry said. "Whether you believe we should have animals of this magnitude in captivity."
To the rescue in Thailand
Thailand banned logging from forests in 1989, a blessing and curse for its working elephants (and for their masters, known as mahouts). They were sold for logging in neighboring Myanmar or ended up in circuses, zoos and camps giving rides to tourists. Many were abandoned. Some starved to death.
For years, Sangduen Chailert, known as Lek, had felt in her heart that she had to save the Asian elephants of her childhood in northern Thailand. In 1996, she founded the Elephant Nature Park in Chiang Mai. It is home to around 40 elephants, most of them injured or old, all of them rescued by Lek. "They think of me as one of the herd."
In Chad, the ivory poachers have upgraded to automatic weapons.