This oral presentation has more general information on platypuses than the publication

1. Platypus Surfing: In Search of the Perfect Wave
Authors:
Dr Ann Morrison, School of Future Environments, Auckland University of Technology, Auckland, New Zealand;
Dr Hannah Larsen, Wildlife Conservation and Science, Zoos Victoria, Melbourne, Victoria, Australia;
Caroline Fieldus. Australian Bush team, Zoos Victoria, Melbourne, Victoria, Australia;
Associate Professor Alexander Kist, School of Mechanical and Electrical Engineering, University of Southern
Queensland, Toowoomba, QLD, Australia;
Dr Ananda Maiti. Information and Communication Technology, University of Tasmania, Hobart, TAS, Australia

2. Sam is a 15 year old 2.2 kilo male Platypus who was
rescued from the wild and has been at Melbourne Zoo
for 14 years
Platypuses, especially but not only males are often solo creatures, although in
the wild they may share a stretch of water, but still lead solitary lives.

3. Healsville Sanctuary, platypus male
cared for since birth, but still need
protective clothing to protect from
venomous spurs
Healsville Sanctuary, platypus male
cared for since birth, but still need
protective clothing to protect from
venomous spurs

4. The platypus is a duck-billed, beaver-tailed, otter-footed, egg-laying aquatic creature
native to Australia. the male of the species is also one of the world’s few venomous
mammals! He delivers venom through ankle spurs (females aren't venomous). The
venom is composed of defensin-like proteins, or DLPs, three of which are only found in
the platypus. The venom can severely hurt (but not kill) humans, although it can be
lethal to smaller animals.

5. The platypus is a bottom-feeder that uses its beaver-like tail to steer and its
webbed feet to propel itself through the water while hunting for insects,
shellfish, and worms. The watertight nostrils on its bill remain sealed so that the
animal can stay submerged for up to two minutes as it forages for food.

6. The platypus has no teeth, so the platypus stores its "catch" in its cheek
pouches, returns to the surface, mashes up its meal with the help of gravel
bits hoovered up enroute, then swallows it all down.

7. When they dive underwater, platypuses are basically sightless
and unable to smell anything.
Folds of skin cover their eyes, and their nostrils seal up to
become watertight.
Their bills have electroreceptors and mechanoreceptors
that allow them to detect electrical fields and movement,
respectively. But since their mechanoreceptors will be attuned
to any movement, electroreceptors are necessary to detect
living organisms for eating after they dig through the seabed.
When they dive underwater, platypuses are basically sightless
and unable to smell anything.
Folds of skin cover their eyes, and their nostrils seal up to
become watertight.
Their bills have electroreceptors and mechanoreceptors
that allow them to detect electrical fields and movement,
respectively. But since their mechanoreceptors will be attuned
to any movement, electroreceptors are necessary to detect
living organisms for eating after they dig through the seabed.

9. Sam’s enclosure at Melbourne Zoo

10. Sense of Scale, 2 ladders to climb in each end of the ‘tank’

11. Cleaning Utensils Needs scrubbing down every week

12. Filter over internal tank
pump
Becomes something he swims in and around

14. When not foraging, the Platypus spends most of the time in its
burrow in the bank of the river, creek or a pond. Use rocky
crevices and stream debris as shelters, or they burrow under the
roots of vegetation near the stream.
.

16. The Back of House Sleeping Tunnels

17. Whole area back of
house for Sam to move
around in the tunnels,
rocks and greenery for
him to nest/sleep/ in.
Sliders and gates to
allow him to move
around

26. Infra red lighting during
the day—nocturnal by
nature

27. Purpose
investigate the best methods to implement a platypus triggered
wave enrichment so that the platypus can play in the waves
when and how often and for how long he likes (Sam has been
observed enjoying playing in waves) to enrich their environment
and improve their quality of life—GIVE CHOICES
extend knowledge on the effects of water play and movement of
water and patterns by the platypus over longer periods of time
research can inform further interactive water movement,
patterns and rhythm in other tanks and benefit animal welfare

29. Remotely
accessed
interface so
the keepers
can easily
adjust and
control the
environment
according to
Sam’s needs

30. Middle: Two stainless steel electrodes on the outside are used to
emit the electrical signal & (IMU) (detects acceleration)
50c piece for scale
Right: the floatable 3D
Printed food grade ball
it all gets contained in

31. The system
• The sensor is enclosed in a pressure water pipe and houses an
internal inertial measurement unit (IMU) (detects acceleration),
signal generator and the whole ball system is weighted so it floats
just below the surface of the water.
• All parameters such as trigger threshold, duration, inactive periods
and patterns are configurable. The sensor ball is equipped with an
internal inertial measurement unit (IMU) and the signal generator.
Both are configured by the wave controller.

32. Food Grade 3D
Printed
Floatable Ball
contains the
IMU sensor
and
electronics—
keeps
waterproof and
floating on the
surface

33. Sensor Control System
In order to trigger a wave event, the Platypus must swim up to and
interact with the IMU sensor.
To encourage this, an electromagnetic wavelength, loosely mimicking but
not exactly replicating those emitted by Platypus prey species, will be
emitted by the sensor for a period of 5-10 minutes (Pettigrew, Manger, &
Fine, 1998) to avoid confusion, frustration and disappointment—not food!)
Eventually, for each wave sequence, a different electromagnetic wavelength
will be emitted, providing an opportunity for the Platypus to learn what
wavelength emission is associated with what wave sequence.

34. Right secure waterproof attachment to
floatable ball, keeps electronic wiring secure
Left: The pump controller is implemented using a programmable logic controller
(PLC). PLCs are ruggedised industrial digital computing units widely used in control
applications. Contained in the hard wire that suspends from the ceiling

35. The controller transfers
information to the sensor,
which in turn controls the
pump and wave patterns
The wave controller, a custom-built microcontroller unit,
connects to the PLC and the sensor ball. It has a WIFI
interface to connect to the zoo wireless network and an
inbuilt web server to generate the user interface.

37. Ananda programming back of house of the tank

38. Some of the team:
From Left: Ananada Maiti, Hannah Larsen, Caroline Feldus and Alexander Kist

39. The three wave treatments are
1) Lagoonal Random mode, which simulates a low-energy lagoon
environment. The speed of the pump is changed slowly to recreate gentle
currents found at a lagoon. Emit wavelengths of 250 Hz
2) Tank-fill Random mode simulates a higher energy wave experienced
during a tank fill. The pump changes speed frequently to simulate rolling waves
and surges similar to tides. Emit wavelengths of 450-600 Hz
3) Gyre mode creates a flow pattern of uniform clockwise and counter-
clockwise flow levels pulsing at selected intervals. Emit wavelengths of 350 Hz
If triggered (as described below) by the Platypus, each wave sequence will last
between 60 and 300 second

40. Wave Treatments:
In consultation with the keepers at MZ, three specific wave forms
have been designed for this project:
However, INITIALLY we will consult and decide on using only
one type of wave treatment with a single signal to reduce
complexity of the design in the first implementation of the project
Make sure of his responses first
Will use the choice between signal types and waves treatments
as a second part of the project.

41. Observation, Video and Logged data collection
Video recordings of the Platypus interacting with each of the
wave treatments will be taken by the observer throughout the
study in order to characterise the interaction style and any
changes between treatments or over time.
An SD card linked to the system will collect all data from activity
with the waterproofed interactive electrode sensor placed in the
water. This logged data can supplement the information obtained
from observations and scheduled video recordings.

42. https://www.youtube.com/watch?v=HM4AQE6pe-
8&list=PLmE3uN0sf7ybbiXTxPYDvBA27iDnKbySX&i
ndex=2&ab_channel=Animal-
ComputerInteractionConference

43. Trial Design
Testing of the enrichment device will take place at Melbourne Zoo in the display tank for the male
Platypus, Sam.
Prior to assessing the effectiveness of the wave machine as an enrichment device, a short pilot study
will be conducted to assess if there are any negative behavioural responses to the device. This pilot
study will last for three days and involve:
Two frequency emissions per day at the maximum duration (10 minutes). A single frequency will be
tested each day.
Two wave events at the maximum duration (5 minutes), regardless as to whether the Platypus has
triggered these events. A single type of wave event will be tested each day.
During this pilot study, the Platypus’ response to the emissions and waves will be monitored by an
observer in the visitor area. Any overt negative response (i.e. rapid retreat, aggression towards
sensor, initiation of stereotypic swimming behaviour) to either the emissions or the waves will trigger
the observer to immediately cease the emissions or waves. All other behaviours will be recorded
continuously while the enrichment device is active. Keepers will also record any changes in feeding
behaviour or participation in normal husbandry tasks (e,g, training, other enrichment). If during this
pilot study a type of wavelength or wave pattern initiates a negative response, this treatment will not
be included in the following trial.

44. Assessing Treatments
In order to assess the effectiveness of the different functions of the
wave machine as enrichment for Platypus, each emission and
associated wave function will be considered as a different treatment.
All treatments will be delivered Monday – Friday (excluding public or
school holidays) to control for the number of visitors.
Treatments will consist of 2-day replicates and be repeated twice over a
six-week period following an ABACADA design for multiple treatments

45. Maintaining Usual Routines
Normal husbandry routines will not be influenced by the
treatment schedule, however all attempts will be made by the
keeping team to maintain stable husbandry routines to eliminate
other sources of variation that might influence the Platypus’
behaviour.
Tank cleans will be scheduled for non-treatment days, and a
control day (A) or weekend day (X) be scheduled either side of
the tank clean days. No other wave based enrichment will be
used during this study period

46. Considerations
On each treatment day, the number of electromagnetic emissions, and
thus opportunities for the Platypus to engage with the wave
enrichment, will be randomly allocated between 2 and 6.
This safeguards the enrichment device becoming ‘less stimulating’ or
even negative.
The time at which emissions begin, the duration of each emission and
the duration of the waves will also be randomly allocated throughout
the study.
This is to ensure that the Platypus is not able to predict when
emissions (and thus the opportunity to interact with waves) will occur,
which has the likelihood of increasing anticipatory circling behaviour.

47. During this study period, a single observer will conduct
behavioural observations Monday – Friday from 9am to 4:30pm
(visitor hours), using a combination of scan sampling and
continuous sampling.
Scan sampling will occur at 5-minute intervals to record state
behaviours and generate an activity budget for the Platypus,
identifying the proportion of time he spends engaged in various
behaviours such as swimming, foraging, stereotypies, and
engaging with enrichment.
Continuous sampling will be conducted on treatment days (B,
C, and D) to record the number of times the Platypus activates
the enrichment device, the duration of which he engages
directly with device (both sensor and waves) and the time of
day in which this occurs. On control (A) days, the number of
times the Platypus interacts with the sensor will be recorded.

48. Week Mon Tues Wed Thurs Fri Sat Sun
1 A A B B A X X
2 A C C A A X X
3 D D A A A X X
4 A A A B B X X
5 A A A C C X X
6 A D D A A X X