Walrus Gestation Calculator
Last updated
A walrus's gestation period is about 460 days, or roughly 15 months, though it ranges from 450 to 480 days depending on breed and individual animal.
Calculate a calf due date
Estimated calving date
Saturday, 8 January 2028
Earliest
29 Dec 2027
Latest
28 Jan 2028
0 of 460 days elapsed
Milestone timeline
| Day | Milestone | Date |
|---|---|---|
| 0 | Mating in late winter, in the water near the sea ice | 5 Oct 2026 |
| 100 | Delayed implantation ends; the embryo attaches and begins growing | 13 Jan 2027 |
| 300 | Fetal growth accelerates | 1 Aug 2027 |
| 460 | Expected calving, usually in spring on the ice | 8 Jan 2028 |
How to use the walrus gestation calculator
- 1. Choose what you know. Enter the breeding date to get a due date, or switch to the target due date mode to work backwards to the breeding date you need.
- 2. Refine the inputs. The calculator uses the 460-day average for this species.
- 3. Plan around the range. Use the earliest and latest dates and the milestone timeline to schedule checks, feed changes and preparation of the calving area.
How long is a walrus' gestation period?
The average is 460 days from breeding to calving, about 15 months. Anything between 450 and 480 days is normal, and a typical litter is 1 calf. Treat the calculated date as the middle of that window rather than a fixed appointment.
Walrus gestation table: breeding date to calving date
Breeding dates one week apart with the matching calving date at 460 days.
| Breeding date | Expected calving date |
|---|---|
| 5 Oct 2026 | 8 Jan 2028 |
| 12 Oct 2026 | 15 Jan 2028 |
| 19 Oct 2026 | 22 Jan 2028 |
| 26 Oct 2026 | 29 Jan 2028 |
| 2 Nov 2026 | 5 Feb 2028 |
| 9 Nov 2026 | 12 Feb 2028 |
| 16 Nov 2026 | 19 Feb 2028 |
| 23 Nov 2026 | 26 Feb 2028 |
| 30 Nov 2026 | 4 Mar 2028 |
| 7 Dec 2026 | 11 Mar 2028 |
| 14 Dec 2026 | 18 Mar 2028 |
| 21 Dec 2026 | 25 Mar 2028 |
Working backwards from a target calving date
If you want calfs on the ground in a particular week, switch the calculator to target date mode and enter the date you are aiming for. It subtracts 460 days to give the breeding date to book, plus the earliest and latest service dates that still land inside your window.