The massive mom-to-be was finally captured at the Sonoma mud flats near Highways 37 and 121 and was then moved to Chimney Rock at Point Reyes.
PHOTOS: Elephant seal captured in Sonoma County
The 900-pound elephant seal was released in the dark in hopes of not disturbing the others on the protected beach. A male elephant seal, also called a bull, was heard lurking in the night.
"The big bulls are definitely a risk for us, they're dangerous to people, absolutely. They heard the noise. They heard the jostle. They wanted to know who it was. That was them trying to find out who was in their territory," said Laura Chapman of the Marine Mammal Center.
Earlier Tuesday, marine mammal experts spent a second day preventing the determined female elephant seal from crossing Highway 37 near the Highway 121 split.
Ultra sound shows #elephantseal is pregnant. Leaving Hwy 37 to drop her off at Pt. Reyes. @TMMC @CHP_GoldenGate pic.twitter.com/gWc19shSSr
— alan wang (@AlanWangABC7) December 30, 2015
"Elephant seals in general are stubborn. You usually have to use twice as much pressure, or a little bit of effort, more than other animals," said Barbie Halaska of the Marine Mammal Center.
She had already crawled out onto the highway the day before, causing a huge traffic jam.
"We were able push her back in the water, and we were hoping she would go back out with the tide last night. Unfortunately, she was still here in the morning," said Marine Mammal Center director of veterinary science Shawn Johnson.
#Tolay the #elephantseal has been sedated and placed onto tarp. @abc7newsBayArea pic.twitter.com/3KZSnP1ola
— Katie Marzullo (@KatieABC7) December 29, 2015
Finally, the wayward elephant seal found a culvert. She swam down the creek, under Highway 37 and plopped down in the field she was trying to reach. Marine mammal experts quickly tranquilized her and performed an ultrasound.
"We did see a fetus, so she is pregnant. It will be great to get her back out where she can have her pup on the beach where she should," said Johnson.
Rescue workers named her Tolay after the creek she swam down. Tolay is now on the beach at Point Reyes where she can avoid the traffic and have her pup, where elephant seals have been breeding for more than 150 years.
We are still on scene SR 37 E/ of SR 121 with a sea lion that wants no part of us. Rdwy clear but traffic is heavy pic.twitter.com/q2VfypMQI4
— CHP Marin (@CHPMarin) December 28, 2015
#Elephantseal #Tolay has moved... She's now under this bridge. @abc7newsBayArea pic.twitter.com/kAYeKloxXn
— Katie Marzullo (@KatieABC7) December 29, 2015

Bumper to bumper on SR37 in #Sonoma where pregnant #elephantseal is hanging out. @abc7newsBayArea pic.twitter.com/GYeUWST5DE
— Katie Marzullo (@KatieABC7) December 29, 2015
View from the other side of the #elephantseal. @abc7newsBayArea pic.twitter.com/2zr5OKXRVr
— Katie Marzullo (@KatieABC7) December 29, 2015
Marine Mammal Center going back in the mud to steer #elephantseal in right direction. @abc7newsBayArea pic.twitter.com/HgpnRRduOL
— Katie Marzullo (@KatieABC7) December 29, 2015
Gentle persuasion... pic.twitter.com/A2rskClXEi
— Katie Marzullo (@KatieABC7) December 29, 2015
She is huge! Estimated 900lbs. pic.twitter.com/lWcGH39yLz
— Katie Marzullo (@KatieABC7) December 29, 2015
This round goes to the #elephantseal... The canoe lost ground. @abc7newsBayArea pic.twitter.com/zoAWU9LCIb
— Katie Marzullo (@KatieABC7) December 29, 2015
Now we're headed in the right direction! @abc7newsBayArea pic.twitter.com/gAc9qOsJ8I
— Katie Marzullo (@KatieABC7) December 29, 2015
Spoke too soon... She's pushing them back. @abc7newsBayArea pic.twitter.com/ZnglKzRSHU
— Katie Marzullo (@KatieABC7) December 29, 2015
Now going in opposite direction... @abc7newsBayArea pic.twitter.com/p2VB4i1bbf
— Katie Marzullo (@KatieABC7) December 29, 2015
Vets preparing tranquilizer. #Tolay @abc7newsBayArea pic.twitter.com/rrbGixJDJe
— Katie Marzullo (@KatieABC7) December 29, 2015
How many people does it take to move a 900lbs. #elephantseal? @abc7newsBayArea pic.twitter.com/ZkT1vxW2Re
— Katie Marzullo (@KatieABC7) December 29, 2015
Almost on the truck... #Tolay #elephantseal @abc7newsBayArea pic.twitter.com/ZfYvIQP1qM
— Katie Marzullo (@KatieABC7) December 29, 2015
#Tolay is on her way... #elephantseal @abc7newsBayArea pic.twitter.com/Mwzp6RhP2w
— Katie Marzullo (@KatieABC7) December 29, 2015