Ultrasound of Asian Elephant Nhi Linh at Smithsonian's National Zoo

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For the first time in nearly 25 years, animal care staff at the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) in Washington, D.C., are preparing for the highly anticipated birth of an Asian elephant calf. In April 2024, the Zoo’s 44-year-old male elephant Spike bred with 12-year-old female Nhi Linh [NEE-lin]. Asian elephant pregnancies last 18 to 22 months on average. Staff are closely monitoring Nhi Linh and are cautiously optimistic she will deliver a healthy calf between mid-January and early March next year. Every birth is a boon for this endangered species, as fewer than 50,000 Asian elephants are left in the world.

As Nhi Linh’s due date approaches, the Zoo will provide updates through its website, e-newsletter, Facebook, X and Instagram channels. At the Elephant Trails exhibit, visitors can see the Zoo’s herd up close and meet their care team during the 3 p.m. daily keeper talk. Worldwide, fans can follow the elephants’ stories and stay connected via the Elephant Cam on the Zoo’s website.

Over the past three years, the elephant team has built positive relationships with Nhi Linh. Keepers train the elephants using positive reinforcement, a type of operant conditioning where they pair desired behaviors with rewards in the form of attention and food. Nhi Linh voluntarily participates in her own husbandry and medical training, including blood draws. A few months after Nhi Linh bred with Spike, staff used blood samples to confirm she had successfully conceived. These diagnostics are also used to track the elephants’ hormones. Once her progesterone levels reach baseline, the team will know birth is imminent. Nhi Linh also voluntarily participates in ultrasounds, allowing staff to monitor fetal development, heartbeat and movement. To help her maintain optimal body condition, staff take Nhi Linh through strength and flexibility exercises daily. Some of the behaviors she has learned—such as extending her legs forward on cue—will be utilized if the calf needs better access to nurse.

For more than 50 years, Smithsonian scientists at NZCBI have led research on elephant care and conservation in Washington, D.C., and Southeast Asia. The Zoo’s elephants are a critical part of this work. These animal ambassadors participate in studies that help scientists better understand Asian elephant behavior, reproduction, endocrinology, disease (including elephant endotheliotropic herpesviruses, or EEHV), genetics and movement ecology. They share information with accredited institutions to advance elephant care in zoos. In elephant range countries, Smithsonian scientists conduct research alongside key conservation organizations, universities, government agencies and local community partners. Together, they develop strategies and solutions to help humans and elephants live safely side-by-side, from rewilding former work elephants to safeguarding lives and crops on lands that have been converted from forests to farms.