You'll still see burros carrying heavy loads in Puerto Vallarta. For some of their handlers, it's merely a tradition and a tight grip on a long-held belief that beasts of burden are more reliable and less expensive than modern trucks. 

But in the steep hills that surround Puerto Vallarta, a burro is often the only 'device' that can safely and efficiently carry heavy loads up slippery slopes while building a house before the roads are complete. They can also carry loads up staircases and ramps that otherwise would require long and difficult man-hours.

These sturdy animals also are able to navigate to and from the several rivers to harvest clean sand for building. With all the beaches in town, you might wonder why this is an issue, but beach sand contains salt from the sea, which makes a very poor concrete mix. So don't be surprised when you see a few burros getting loaded up with sand by the river, on its way to a building site which isn't yet accessible to trucks.

Burros used to be a way of life for Mexico in cities, towns, and farms, but this has been changing. "There used to be 50 in every town. Now there is one, if that," said Nicolas Vazquez Ortega, a ranch manager. "Before you used to see packs of mules and donkeys in the fields when you were driving along the road. Now they are disappearing."

Although it seems as improbable as Hawaii running out of pineapples, Mexico has a shortage of donkeys. As farmers abandon the countryside for big cities, move to the United States or shift to tractors and cargo trucks, burros -- long a backbone of Mexican agriculture and a symbol of Mexican life -- have become increasingly scarce.

This trend has so alarmed officials in Jalisco, one of Mexico's most important agricultural states, that they are planning to import donkeys from Kentucky to revive the dwindling population. The project, they said, will bring economic benefits to ailing rural areas, where many poor farmers still depend on beasts of burden.

Donkeys, first brought to Mexico by conquering Spaniards at the turn of the 16th century, have long been a stereotype of rural Mexican life. Even today, said Martin Martinez Cervantes, a Jalisco rural development official, some tourists still expect to find "every Mexican riding a donkey."

But those days are gone. In fact, many farmers have shunned donkeys because of their negative association with poverty and backwardness, officials said. Now, as the animals have started disappearing, people are "realizing their importance," Martinez said.

Both donkeys, known as burros throughout Mexico, and mules, produced by cross-breeding horses and donkeys, have gained belated respect as their numbers have diminished. Farmers say they cause less damage than machines amid the tight rows of blue agave, the spike-leaved plants that produce tequila. Coffee growers in other states say they get better traction than trucks on highland slopes. In many remote areas with no roads, they are still the only ride home. And here in Puerto Vallarta, surrounded by mountains, the loyal burro still finds plenty of work.

The animals provide a stable living for their owners, and after working for 10 or so years, are usually 'semi-retired' from daily toil, and they live out their years in relative relaxation. A few get dressed up and shown off in town for parades and fiestas, and a particular beauty can be found almost daily on Insurgentes Street, across from the flea market or next to the HSBC bank, waiting for you to visit and have a picture taken.