After evaluating Shanti's reproductive history, there's a small possibility she could be pregnant.
Shanti's Reproductive History:
0.1 Bella (Date of Birth: August 17 2004)
2 years, 1 month, and 14 days between the birth of Bella and Mac
1.0 Mac (Date of Birth: October 1 2006)
3 years, 7 months, and 4 days between the birth of Mac and Baylor
1.0 Baylor (Date of Birth: May 5 2010)
3 years, 9 months, and 3 days between the birth of Baylor and Duncan
1.0 Duncan (Date of Birth: February 8 2014)
3 years, 5 months, and 4 days between the birth of Duncan and Joy
0.1 Joy (Date of Birth: July 12 2017)
In August of 2004, Shanti gave birth to her first calf Bella but she rejected her daughter which resulted in the handraising of Bella. Shanti conceived in November or December of 2004 as she gave birth to her second calf Mac in October of 2006.
Given Shanti's reproductive history, she could be pregnant but the probability is low.
However, the Houston Zoo may be breeding Shanti and Tess to Thai soon after the birth of a calf. At 53 years old, Thai has far exceeded the median life expectancy of a captive bull Asian elephant. The Houston Zoo has probably come to the realization that the reproductive clock is ticking for Thai so they're producing as many calves through him within the next decade to ensure his genetics are well represented before his passing.
